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ccie lab dumps Considerations for system migration to cloud servers

ccie lab dumps Considerations for system migration to cloud servers

 Enterprises often encounter many problems when they migrate their existing systems to cloud servers.For example: data loss, website crashes, database errors, etc. ccie lab dumps,\.These problems can lead to loss of time and resources, resulting in damage to the company's interests.As more and more companies move their servers to the cloud, these issues are becoming more and more obvious.ccie lab dumps.How should we reduce the chances of these problems and provide the least interference to the enterprise to smoothly implement cloud migration?

 First, what are the benefits of server migration to the cloud?

 1. Reduce investment costs;

 2.The latest operating system and the latest infrastructure;

 3. It is easier to maintain and manage;

 4. Higher flexibility and scalability;

 5. Longer running time and a good business chain.

   Before starting a migration, you first need to evaluate your internal data. See if these applications or data really need to be migrated to the cloud, and it is completely unnecessary to migrate unwanted data to the cloud.ccie lab dumps.Once the enterprise marks the data that needs to be migrated, it can be used to calculate the required cloud resources and related costs. Importantly, this process can also be used to classify and prioritize workloads, which can reduce costs.

 Then there is the test, to ensure a trouble-free migration before the full data migration and start of the cloud server exit.

 1, functional testing: software and cloud server management function testing, and testing end-to-end applications for performance issues.

 2, integration testing: test the integration between the cloud and legacy systems and SaaS, paying special attention to any interruptions in the chain that will reduce or hinder performance.

 3, security testing: Recently, because of the increase in ransomware and malware, it is very important to ensure that all systems and applications have strong security.

 4. Scalability and performance testing: The most critical advantage of migrating to the cloud is its scalability. ccie lab dumps.It must be ensured that the system can scale as expected. Scalability and performance testing includes creating stress and load tests to ensure that cloud servers can maintain performance levels at maximum capacity.

 Be clear when testing, the nature of the cloud environment and the traditional environment are different, running the perfect data on the traditional server, the results running on the cloud computing solution may be completely different.In the migration process, there are many points and reasons that can lead to instability and failure, such as old systems, aging hardware and energy requirements, tolerances.

 In the testing process, try to consider the test content in detail, and must not perfuse the test, but carefully prepare and do everything possible.

 In short, cloud computing solutions such as cloud servers can provide dynamic, powerful platform support for the company's best ideas and innovations, but only if the cloud has been carefully tuned to respond to your website, applications and business needs. Whether it is integration with legacy systems or a large elastic expansion.

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ccie lab dumps R&S - -How far is IPv6

ccie lab dumps R&S---How far is IPv6 

First, understand IPV6

When using the mobile app, I found that there is a small line "Supported IPv6" at the bottom of the welcome page. According to global IPv6 statistics released by Google, by the end of November 2018, the global IPv6 penetration rate has exceeded 25.04%, while China's IPv6 penetration rate is only 2.93%.ccie lab dumps.In 2019, both operators and Internet companies have begun to popularize IPv6 on a large scale. So what is IPv6?

 When it comes to IPv6, you can't help but mention the IPv4 protocol you are using now. "The father of the Internet" Wendun Joseph created the Internet communication protocol "IPv4" in 1977, allowing global computers to connect to each other. An IP address is a series of numbers assigned to each computer, website, or other networked device, and each IP address is unique.ccie lab dumps. Since the IP address length specified in IPv4 is 32 bits, the rapid development of the Internet of Things has caused the current IPv4 address to be warned. As of June this year, China's fixed-line Internet users are 751 million, mobile Internet users 724 million, but IPv4 addresses are 338.45 million, and the average IPv4 address per fixed-line Internet users in China is only 0.45.

 IPv6 uses a 128-bit address length, which claims to be a website for every grain of the world. Ccie lab dumps.It is commonly known as the "next generation Internet." In the design process of IPv6, in addition to solving the address shortage problem once and for all, it also considers other problems that are not well solved in IPv4, mainly end-to-end IP connection, quality of service (QoS), security, multicast, mobility, plug and play, etc.

  Second, the advantages of IPv6:

 Compared with IPV4, IPV6 has the following advantages:

 1. IPv6 has a larger address space. In IPv4, the IP address length is 32, and the maximum number of addresses is 2^32. But the length of the IP address in IPv6 is 128, that is, the maximum number of addresses is 2^128. Compared with the 32-bit address space, its address space has increased by 2^128-2^32.

 2. IPv6 uses a smaller routing table. Pv6 address allocation begins with the principle of aggregation. Ccie lab dumps.This allows the router to use Entry in the routing table to represent a subnet, greatly reducing the length of the routing table in the router, and improving the speed at which the router forwards packets.

 3. IPv6 adds enhanced multicast support and flow control. This makes the multimedia application on the network have a great opportunity to develop, also provides a good network platform for QoS control.

 4. IPv6 has added support for Auto Configuration. This is an improvement and extension of the DHCP protocol, making the management of the network (especially the local area network) more convenient and faster.

 5. IPv6 has higher security. In the IPv6 network, users can encrypt the data of the network layer and verify the IP packets. Ccie lab dumps.The encryption and authentication options in IPV6 provide the confidentiality and integrity of the packets. Greatly enhance the security of the network.

 6. Allow expansion. IPV6 allows the protocol to be extended if new technologies or applications are needed

 7. A better head format. IPV6 uses a new header format with options that are separate from the base header and can be inserted between the base header and the upper layer data if needed. This simplifies and speeds up the routing process because most of the options do not need to be routed.

 8. new options. IPV6 has some new options to implement additional features

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 Ccie lab dumps

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Cisco ccie exam 5G and WIFI6, still can't tell?

Cisco ccie exam 5G and WIFI6, still can't tell?

Ⅰ. the opening:

On October 3, 2018, the Wi-Fi Alliance officially incorporated WiFi based on the 802.11ax standard into the regular army and became the sixth generation WiFi technology. The WiFi specification was renamed, the standard 802.11n was renamed to WiFi 4, the standard 802.11ac was renamed to WiFi 5, and the new standard 802.11ax was renamed to WiFi 6. (Of course, the previous generation of 802.11b/a/g can be chased as WiFi 1/2/3)

Not only changed the naming convention of WiFi, but also in the network connection of WiFi devices. Also all use the new UI icon. Cisco ccie examThe icon will display the level of the WiFi network you are currently connected to through the most intuitive numbers.

Wi-Fi is well known to us. Wi-fi has evolved from 802.11b in 1999 and has gone through five generations. The Wi-Fi Alliance announced the simplification of the name of the new Wi-fi to Wi-fi6 when it introduced the new generation of 802.11ax standards. Cisco ccie exam .After all those years, the Wi-Fi Alliance finally opened up. It is much better to use the size of the number to standardize the WiFi specification. Finally, you can recommend the latest products to your friends without explaining the complicated specifications. So what is WiFi 6? What's so good about WiFi 6(11ax)?

Ⅱ.what is WiFi 6?

Wi-Fi 6 is based on the new IEEE 802.11ax standard, so these two terms may be interchanged.

Converted Wi-Fi version:

Wi-Fi 1 is 802.11b released in 1999.

Wi-Fi 2 is 802.11a and also released in 1999.

Wi-Fi 3 is 802.11g released in 2003.

Wi-Fi 4 is 802.11n and was released in 2009.

Wi-Fi 5 is 802.11ac released in 2014.

Wi-Fi 6 is a new version, also known as 802.11ax.

Ⅲ, the difference between WiFi4 WiFi5 WiFi6

WiFi 4

802.11n was out in 2009. With 40MHz bandwidth and MIMO black technology, it upgraded the WiFi theoretical bandwidth from 54Mbps at 11a/g to 600Mbps (150Mbps×4 spatial streams), and 11n supports 2.4G/5G band at the same time. Perfectly replace the old standard.

WiFi 5

That is, 802.11 ac, was out in 2013. The original version (Wave 1) boosted WiFi single-stream bandwidth to 433Mbps with 80MHz bandwidth. The second edition of 2016 (Wave 2) draws on the characteristics of part 11ax and doubles the bandwidth to 160MHz. Cisco ccie exam.Although 11ac theoretically supports 8 spatial streams, it basically only achieves 4×4 (80MHz) or 2×2 (160MHz) in the home WiFi market, that is, the theoretical bandwidth is 1733Mbps, which is very different from the 11ac limit bandwidth (6.9Gbps).cisco ccie exam But because wireless network transmission is based on wired networks. Therefore, the current mainstream of the family is the background of the Gigabit network. WiFi 5 did not become a network bottleneck.

It is worth noting that 11ac only supports the 5G band. Therefore, it is technically impossible to replace 11n supporting the 2.4G frequency band. Current mainstream home wireless routers can only choose to support both WiFi 4 and WiFi 5. Therefore, WiFi 5 is an upgrade iteration of WiFi 4, which is somewhat less rigorous.

WiFi 6

Based on 802.11 ax technology, this technology is strictly in the womb. The draft is still under discussion and is expected to be officially standardized in 2019. However, most of its technical specifications have been made public, so some manufacturers have made the specification into products to grab the market. 11ax supports the 2.4G/5G band at the same time, which is the sixth generation WiFi iteration standard in the true sense. Cisco ccie exam.The 11n and 11 ac products on the market will be replaced in the future.

In addition, 11ax also brings a complete version of mu-mimo, supporting 8 terminals uplinking/downlink mu-mimo, and introducing OFDMA black technology to realize another parallel transmission capacity complementary to mu-mimo, which is more flexible and practical than mu-mimo.

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Cisco ccie exam 5G and WIFI6, still can't tell?

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cisco ccie exam A brief look at MPLS

cisco ccie exam A brief look at MPLS Multi-Protocol Label Switching (MPLS) is a new technology that uses tags to guide data at high speed and high efficiency on an open communication network. cisco ccie exam.Multi-protocol means that MPLS can not only support multiple protocols at the network layer level, but also be compatible with multiple data link layer technologies of the second layer. Multi-Protocol Label Switching (MPLS) is a new generation of IP high-speed backbone network switching standard, proposed by the Internet Engineering Task Force (IETF). MPLS uses labels for data forwarding. When a packet enters the network, it is assigned a short-length label of a fixed length and encapsulates the label with the packet. During the entire forwarding process, the switching node forwards only according to the label. cisco ccie exam.MPLS is independent of Layer 2 and Layer 3 protocols, such as ATM and IP. cisco ccie exams .It provides a way to map IP addresses to simple fixed-length labels for different packet forwarding and packet switching techniques. It is an interface to existing routing and switching protocols such as IP, ATM, Frame Relay, Resource Reservation Protocol (RSVP), Open Shortest Path First (OSPF), and more. In MPLS, data transmission takes place over a Label Switched Path (LSP). The LSP is a sequence of labels for each node along the path from the source to the terminal. cisco ccie exam.MPLS is primarily designed to address network issues such as network speed, scalability, quality of service (QoS) management, and traffic engineering, as well as address broadband management and service requests for next-generation IP hub networks. Multi-protocol label switching (MPLS) was originally proposed to increase the forwarding speed. Compared with the traditional IP routing mode, it analyzes the IP packet header only at the edge of the network during data forwarding, instead of analyzing the IP packet header in each hop, thus saving processing time. MPLS originated from IPv4 (Internet Protocol version 4), and its core technology can be extended to a variety of network protocols, including IPX (Internet Packet Exchange), Appletalk, DECnet, and CLNP (Connectionless Network Protocol). "Multiprotocol" in "MPLS" refers to supporting multiple network protocols. MPLS is a tag-based IP routing method. These labels can be used to represent hop-by-hop or explicit routing, and indicate quality of service (QoS), virtual private networks, and how traffic affecting a particular type of traffic (or traffic for a particular user) is transmitted over the network. Class information. MPLS uses a simplified technique to perform Layer 3 and Layer 2 conversions.It can provide a label for each IP packet, encapsulate it with the IP packet in a new MPLS packet, thereby determining the transmission path and priority of the IP packet, The MPLS-compatible router reads only the header tag of the MPLS packet before forwarding the IP packet according to the corresponding path, and does not need to read the IP address bit and other information in each IP packet ,so the exchange and forwarding speed of data packets is greatly accelerated.cisco ccie exam Current routing protocols select the shortest path between a given source and destination, regardless of the link's bandwidth, load, etc., and there is no explicit way to bypass the link for lack of security. With explicit routing, you have the flexibility to choose a low-latency, secure path to transfer data. The MPLS protocol implements the conversion of Layer 3 routing to Layer 2 switching. MPLS can use a variety of Layer 2 protocols. The MPLS Working Group has so far standardized the labels used on Frame Relay, ATM and PPP links, and IEEE 802.3 LANs. One of the benefits of MPLS running on Frame Relay and ATM is that it is for these connection-oriented technologies. Brings any connectivity to IP. At present, the main development direction of MPLS is in the aspect of ATM. This is mainly because ATM has strong traffic management functions and can provide QoS services. cisco ccie exam.The combination of ATM and MPLS technologies can fully play a role in traffic management and QoS. the label is the header used to forward the packet, and the format of the header depends on the network characteristics. In the router network, the label is a separate 32-bit header; in the ATM, the label is placed in the virtual circuit identifier/virtual channel identifier (VCI/VPI) cell header. A key to MPLS scalability is that the tag only makes sense between the two devices communicating. At the core of the network, the router/switch only interprets the tags and does not parse the IP packets.cisco ccie exam When an IP packet enters the core of the network, the border router assigns it a label. From then on, the MPLS device will view labeled information from start to finish and exchange these labeled packets to its destination. As routing processing is reduced, network latency is reduced but scalability is increased. cisco ccie exam.The quality of service (Qos) type of the MPLS packet can be determined by the MPLS border router according to various parameters of the IP packet, such as the source address, destination address, port number, and TOS value of the IP. Publisher:IE LAB publish Website:http://ielab.network WhatsApp: +8617782638871 Skype:live:ielab.anna cisco ccie exam A brief look at MPLS

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ccie exam fee Analysis of Cisco CEF

ccie exam fee Analysis of Cisco CEF CEF (Cisco Express Forwarding) technology is a new routing switching solution introduced by Cisco. It has good switching performance, enhanced switching architecture and extremely high packet forwarding rate.ccie exam fee The basic functions of traditional routers are route calculation and packet forwarding. Usually based on shared memory architecture, a centralized CPU, which is a single CPU (or multiple CPUs, connected into a router cluster) controls the shared bus and connects multiple interface cards. The card contains a simple queue and other structures, communicates with the CPU, and implements packet forwarding through the shared bus.With the rapid development of the Internet and the emergence of a large number of new service requirements, higher requirements are placed on the routing and switching performance of the network. ccie exam fee.To improve the packet forwarding rate and system performance at the same time, the design of traditional routers and switching devices must be adopted. The architecture was improved and some new design options were added to improve system performance.Switching routers using CEF technology have qualitative changes in architecture, routing, and interface card performance. They are especially suitable for the core layer of large-volume ISP networks, and are also widely used in the backbone of high-speed enterprise networks. CEF has two modes: (1) Centralized: Allows a routing processing module to run an express exchange,which is the FIB and adjacency tables reside in the routing processing module. When the line card is unavailable or does not have the function of decentralized CEF switching, the centralized CEF switching mode can be used. (2) Distributed: (Generally referred to as dCEF) Allows the router's multiple line cards (VIPs) to run the express switching function separately, provided that the line is a VIP line card or a GSR line card. The central routing processor performs functions such as system management/routing and forwarding table calculations, and distributes the CEF tables to a single line card; each line card maintains the same copy of one FIB and adjacency list.ccie exam fee.The line card performs fast forwarding between the port adapters so that the switching operation does not require the participation of the routing switch module. DCEF uses an "internal process communication" mechanism to ensure synchronization of the FIB and adjacency tables between the route processor and the interface card. Exchange algorithm: Ø Process exchange The original Cisco routers used centralized CPU packet switching. All packets were passed to the CPU through the shared bus, searched by the routing table, CRC recalculated, and then passed to the appropriate line card through the shared bus. Ø fast exchange An IP packet arriving at a specific destination address usually causes a packet flow, that is, assuming that the packet has been exchanged to a specific destination, the other is likely to arrive soon.By constructing the cache of the exchange target, it is possible to reduce the number of times the packet finds the same target in the full routing table.ccie exam fee. This "one-time route, then exchange" mode is called fast exchange, and the fast exchange greatly improves the packet forwarding rate of the router, thus becoming The default exchange mechanism on the Cisco router platform.However, it should be noted that changes to the IP routing table will invalidate the cache. In an environment where routing conditions are constantly changing, the advantages of the route cache will be greatly limited. Ø Autonomous exchange The feature of autonomous switching is that some switching functions are offloaded from the CPU. In effect, the routing cache function is moved from the CPU to the secondary switching processor, and the receiving packet on the line card first completes the local routing cache target search in the switching processor, interrupts the CPU if the search fails, and then performs routing.Here, Cisco renames the CPU that periodically calculates the route to the route processor and the auxiliary switch processor to the switch processor. Autonomous switching is performed on the Cisco 7000 Series routers to further improve throughput and other performance.ccie exam fee Ø Distributed exchange With the introduction of the VIP (Versatile Interface Processor) card, the switching system of the router has gradually evolved to a peer-to-peer multiprocessor architecture.Cisco ccie exam. Each VIP card contains a RISC processor, maintains the latest copy of the fast switching cache generated by the routing switch processor, and can independently implement the function of routing and switching, and complete two types of switching at high speed---local VIP exchange and VIP exchange. Ø express exchange As mentioned above, the fast-switching caching mechanism does not scale well in high-speed dynamic routing environments such as the Internet (often with network topology changes, routing changes, route flapping, etc.), and the routing changes cause the cache to be invalid. Rebuilding the cache (that is, the process of performing a "process exchange") is computationally expensive;At the same time, with the rapid development of the Internet and its services, various applications and interactive services based on WEB have increased the number of real-time data streams with a large number of communication times and short communication times, and the contents of fast-switched cache contents are constantly changing. The burden on the cache is increased, resulting in reduced router performance. The CEF Express Exchange Technology is designed to address these shortcomings.Cisco ccie exam CEF is an advanced Layer 3 switching technology designed primarily for high performance, highly scalable Layer 3 IP backbone switching.To optimize the route lookup mechanism for packet forwarding, CEF defines two main components: the Forwarding Information Base and the Adjacency Table.Cisco ccie exam The forwarding information base (FIB) is a lookup table in which the router determines the target exchange. There is a one-to-one correspondence between the FIB entry and the IP routing table entry, that is, the FIB is a mirror image of the routing information contained in the IP routing table. Since the FIB contains all the necessary routing information, there is no need to maintain the routing cache. When the network topology or route changes, the IP routing table is updated and the contents of the FIB change.Cisco ccie exam The CEF uses the adjacency list to provide the information needed for the MAC layer rewriting of the packet. Each item in the FIB points to a next hop hop in the adjacency list. If neighboring nodes can forward each other through the data link layer, these nodes are listed in the adjacency list. Once the adjacency is found, the system writes it to the adjacency list. The adjacency sequence is generated at any time. Each time a neighbor entry is generated, a link layer header information is pre-computed for that neighbor node, and the link is taken. The layer header information is stored in the adjacency list. When the route is decided, it points to the next network segment and the corresponding adjacency entry. It is then used for encapsulation when the packet is CEF exchanged. To view information about the adjacency table, you can use the Cisco IOS command: show adjacency/show adjacency detail. When we look at the adjacency table information, we find the following two main types of adjacency: Host adjacency and Point to Point.Cisco ccie exam The usual display of the Host adjacency type is an IP address, which indicates the adjacent next hop IP address; the Point to Point type display is "point 2point", indicating that this is a point-to-point circuit. There are also other special types, such as Null adjacency, Glean adjacency, etc. CEF is a high-speed switching method designed for high-performance, highly scalable IP backbone networks. From the above introduction, it is not difficult to see that in large-scale dynamic IP networks, CEF can provide unprecedented consistency and stability of exchange.It can effectively compensate for the frequent failure of fast-switching cache entries. The CEF distributed exchange enables each line card to be completely exchanged, providing superior performance.CEF has less memory than fast-switched routing caches and provides load balancing, network accounting, and more. With the help of CEF Express switching technology and other revolutionary innovations, Cisco's GSR routers have achieved great success worldwide. Publisher:IE LAB publish Website: http://ielab.network WhatsApp: +8617782638871 Skype:live:ielab.anna ccie exam fee Analysis of Cisco CEF

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ccie lab dumps Introduction to Frame Relay Technology

ccie lab dumps Introduction to Frame Relay Technology

 Concept introduction

 DTE: The frame relay network provides the ability to communicate data between user equipment (such as routers and hosts). ccie lab dumps.The user equipment is called Data Terminal Equipment (DTE);

 DCE: A device that provides access to a user equipment. It belongs to a network device and is called a Data Circuit-terminating Equipment (DCE).

 UNI: The interface between DTE and DCE is called User Network Interface (UNI);

 NNI: The interface between the network and the network is called the Network-to-Network Interface (NNI).

   Virtual circuit introduction

 According to different virtual circuit establishment methods, virtual circuits are classified into two types: permanent virtual circuits (PVCs) and switched virtual circuits (SVCs). The virtual circuit generated by manual setting is called a permanent virtual circuit. ccie lab dumps.The virtual circuit generated by protocol negotiation is called a switched virtual circuit. This virtual circuit is automatically created and deleted by the Frame Relay protocol. The most widely used method in frame relay is the permanent virtual circuit mode.

 In the permanent virtual circuit mode, it is necessary to detect whether a virtual circuit is available. The Local Management Interface (LMI) protocol is used to detect whether a virtual circuit is available. The LMI protocol is used to maintain the PVC table of the frame relay protocol, including: notifying the increase of PVCs, detecting the deletion of PVCs, monitoring the change of PVC status, and verifying the integrity of links. ccie lab dumps.The system supports three local management interface protocols: ITU-T Q.933 Appendix A, ANSI T1.617 Appendix D, and non-standard compatible protocols.

 The basic working mode of the LMI protocol is that the DTE device sends a status request packet (Status Enquiry packet) to query the status of the virtual circuit at a certain interval. After receiving the status request packet, the DCE device uses the status message immediately. (Status packet) Notifies the DTE of the status of all virtual circuits on the current interface.

 For the DTE side device, the state of the permanent virtual circuit is completely determined by the DCE side device; for the DCE side device, the state of the permanent virtual circuit is determined by the network. In the case where two network devices are directly connected, the virtual circuit status of the DCE side device is set by the device administrator.

 Frame Relay Address Mapping.ccie lab dumps

 The frame relay address mapping is to associate the protocol address of the peer device with the frame relay address (local DLCI) of the peer device, so that the higher layer protocol can be addressed to the peer device through the protocol address of the peer device.

 The frame relay is mainly used to carry the IP protocol. When sending an IP packet, the next hop address of the packet can only be known according to the routing table. Before the transmission, the corresponding DLCI must be determined by the address. ccie lab dumps .ccie lab dumps.This process can be performed by looking up the frame relay address mapping table, because the address mapping table stores the mapping relationship between the next hop IP address and the DLCI corresponding to the next hop.

 The address mapping table can be manually configured or dynamically maintained by Inverse ARP (Reverse Address Resolution Protocol).

 Interworking between Frame Relay Network and ATM Network.ccie lab dumps

 Currently, there are three ways for interworking between a Frame Relay PVC network and an ATM network:

 The first way is to interconnect two frame relay networks through an ATM network. The ATM network receives information from a frame relay network, adapts it to several ATM cells for transmission within the ATM network, and transmits ATM cell recombined frame relay information to another frame relay at the other end of the network. network. In this way, the ATM network can provide a relay transmission channel for the intranet;

 The second way is the interworking between the user equipment on the frame relay network and the terminal using the frame relay protocol in the ATM network. ccie lab dumps.Interworking between the two devices through the function completion protocol and the mapping of the core frame format provided by the ATM 5th Adaptation Layer (AAL5) of the ATM;

 The third way is the interworking between the user equipment on the frame relay network and the terminal that does not use the frame relay protocol on the ATM network. During interworking, the protocol and the core frame format mapping are implemented through the functions provided by the SSCS of the ATM on the AAL5 of the ATM to implement interworking between the two devices.

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 ccie lab dumps Introduction to Frame Relay Technology

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ccie lab dumps SD-WAN can help solve the multi-cloud challenge

ccie lab dumps SD-WAN can help solve the multi-cloud challenge

 Collaboration between SD-WAN providers and cloud service providers helps easily manage cloud connectivity across multiple cloud providers and create a secure, low-latency, cloudy environment.

 As SD-WAN becomes the primary access for remote users to cloud-based applications, and organizations that deploy cloudy environments to optimize performance. It is important for IT professionals to choose a secure, low-latency, easy-to-use SD-WAN technology - a management connection to the cloud provider.ccie lab dumps

 What is multi-cloud?

 multi-cloud is the use of two or more cloud providers to be able to flexibly run applications on the most appropriate platform, and most companies have accepted it.

 Most IT organizations mix internal data centers, applications deployed on the Infrastructure as a Service (IaaS) platform, and multiple Best Software as a Service (SaaS) applications. These multi-cloud environments may be realized through mergers/acquisitions with other companies or the desire of end users to quickly deploy new applications on cloud-based platforms. Regardless of how they achieve this goal, IT organizations are now responsible for the security, management and quality of user experience for all cloud-based applications.ccie lab dumps

 Each cloud environment has its own strengths, weaknesses and cost profiles. For example, most legacy applications and some new applications may remain in the internal data center for security, compliance, and cost reasons. Each IaaS platform has a unique development environment and associated ecosystem that makes it suitable for certain types of applications. For example, Amazon AWS is for e-commerce applications, Microsoft Azure for applications designed around SQL and Active Directory, and Google Cloud for Kubernetes-based container applications.

 Each SaaS platform has the best application and cost profiles for unified communications, office suites, CRM, accounting, and more.

 The challenge for IT leaders is that each IaaS or SaaS provider has a unique set of services, security mechanisms, APIs and management tools. To optimize the quality of the user experience, IT must navigate the connections provided by each IaaS and SaaS provider, such as the provider's local presence. Most IT leaders say managing this complex combination of multi-cloud resources is challenging.ccie lab dumps

 SD-WAN function

 SD-WAN combines multiple physical WAN links into a single logical network and provides traffic prioritization to accelerate application performance for on-premise and cloud-based applications. Using network abstraction, SD-WAN improves the economics of branching connections by enabling organizations to take advantage of the growing bandwidth requirements with inexpensive circuits such as the Internet. SD-WAN is an overlay technology that maps new services over existing physical networks - application prioritization, security, and management.ccie lab dumps

 SD-WAN can be deployed on-premises by IT professionals or as a hosted service by a range of service providers. SD-WAN technology continues to improve features, including enhanced traffic identification and routing, enhanced network security, and better centralized management.ccie lab dumps

 SD-WAN improves multi-cloud access

 SD-WAN leverages its application identification and traffic steering capabilities to better support secure access to multi-cloud environments. IT professionals can set specific business policy metrics for each application and cloud environment and are enforced by the SD-WAN platform. They must prioritize mission-critical applications based on how much delay they can tolerate. For example, IT can set different policy profiles for low-latency traffic, such as unified communications, voice, video, office productivity applications, and general email.ccie lab dumps

 To improve security, IT can set policies about which traffic should traverse which WAN link, such as private MPLS and the public Internet. The SD-WAN platform provides visibility into traffic sources and destinations that can be used for blacklisting to block and whitelist acceleration. They can also isolate suspicious traffic. Encryption and micro-segmentation at the application or platform level can also be used to increase security.ccie lab dumps

 In response to customer needs, SD-WAN providers have increased the ability to identify and route cloud-based traffic. They have established partnerships with leading IaaS providers to accelerate traffic to local presence points. They can launch virtual instances of their SD-WAN platform on the leading IaaS platform (mostly supporting Amazon AWS and Microsoft Azure). The SD-WAN platform also identifies the IP addresses of most leading SaaS providers to apply the appropriate business strategy.

 SD-WAN is a mainstream technology that enables secure and reliable remote and branch user access to applications, no matter where they are located. SD-WAN application identification, traffic control and security features help IT connect and manage access across multiple cloud environments.

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 ccie lab dumps SD-WAN can help solve the multi-cloud challenge

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Ccie certification cost A minute to learn about the misunderstanding of SD-WAN

Ccie certification cost A minute to learn about the misunderstanding of SD-WAN Before we talk about the misunderstanding of SD-WAN, let's take a brief look at what SD-WAN is. SD-WAN, a wide-area software-defined network, is a service formed by applying SDN technology to a wide-area network scenario. Ccie certification cost .This service is used to connect enterprise networks, data centers, Internet applications, and cloud services across a wide geographic area.It is designed to help users reduce their wide area network (WAN) expenses and increase network connectivity flexibility. SD-WAN is more than just a buzzword, it is already bringing benefits to early adopters.Ccie certification cost .The first word about SD-WAN appeared in the public view was published in network computing in September 2014, But in fact, the concept of SD-WAN comes from the earlier emergence of Hybrid WAN, which is to solve the game problem like unstable Internet interconnection in the enterprise market and expensive MPLS VPN.At the same time, in the ONUG Open Network User Forum in 2014, many enterprise users unanimously proposed such application requirements. "SD-WAN is a service that is used to apply SDN technology to a wide area network scenario. Ccie certification cost .This service is used to connect a wide range of enterprise networks, including branch offices and data centers."Although in many consulting reports or vendor solutions, SD-WAN is often limited to the networking scenarios where enterprise branch offices are interconnected.However, based on the definition of SD-WAN, the application scenarios of SD-WAN can be summarized into three categories: enterprise interconnection, data center interconnection and cloud interconnection scenarios. But we still have a lot of misunderstandings about SD-WAN, let's take a look: 1. SD-WAN will replace MPLS: For the time being, MPLS still occupies a prominent position in the market, but SD-WAN has also eroded a part of the city. In an application, MPLS and Virtual WAN are usually deployed together. The most important scenario is still hybrid networking.For high-priority traffic of enterprise users, the MPLS network connection is still used, and the traffic of the backbone network is controlled by Traffic Engineering to ensure the network quality of data transmission;Ccie certification cost .Some branch offices and remote users, choosing to use the SD-WAN Internet connection, can reduce cost and flexible creation. SD-WAN can reduce the company's reliance on MPLS, but it cannot be eliminated. 2. The only benefit of SD-WAN compared to MPLS is the cost: SD-WAN can be used as a SaaS, which is relatively inexpensive compared to custom DIY settings. The plug-and-play concept of edge devices and the point-and-click configuration of services are huge advantages.Ccie certification cost .Compared to MPLS, everything is centralized, GUI-based, and easier to work with.Overall, SD-WAN can save 30% of the cost per year compared to MPLS in the same proportion of bandwidth. SD-WAN is not only cheap, it is easier to manage, operate and maintain. 3. SD-WAN can guarantee QoS: This is only a misunderstanding caused by vendor marketing, SD-WAN can measure and compensate for packet loss, jitter and latency.The loss of packets can be compensated for by using techniques such as forward error correction. Compensation for delays from distance is not possible for the same path.Jitter can be compensated for by using buffers, but this can create delays and can disrupt QoS for real-time applications such as voice and video.Therefore, SD-WAN can detect and measure delay, packet jitter and loss.Ccie certification cost .It compensates for packet loss, but it cannot be used for jitter and latency. It can switch the best path in the available path, and if all the paths are not good, QoS is not guaranteed. 4. Think of SD-WAN as an independent solution: D-WAN technology needs to follow the same strict security standards as other IT infrastructure elements. In particular, pay special attention to the use of branch routers in the SD-WAN process.Ccie certification cost .Although for traditional branch router deployments, it may not be necessary to check the hardware device once it is installed, but this does not apply to SD-WAN routers. Because for SD-WAN routers, it is important to use the latest security patches to ensure device firmware updates.ccie certification cost.Even with some SD-WAN routers with intelligent auto-repair, you can't change the fact that you need to change the security configuration at any time according to the application environment. SD-WAN is a very good technology and has great prospects, but if we only look at it from marketing, it will be a lot misleading. Publisher:IE LAB publish Website: http://ielab.network WhatsApp: +8617782638871 Skype:live:ielab.anna

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Ccie certification cost Link layer discovery protocol ( LLDP)explanation(2)

Ccie certification cost Link layer discovery protocol ( LLDP)explanation(2)

LLDP is an information discovery and advertisement protocol. The LLDP entity mainly maintains two MIB libraries, a local system MIB and a remote system MIB. It can also be seen from its name that one is used to maintain local related device MIB information,Ccie certification cost. and one is used to maintain remote device MIB information.

LLDP initializes and maintains the local system MIB by interacting with several MIB libraries on the right side in the figure above, and advertises local related information. At the same time, when it receives information from other devices, it is updated to the remote system MIB. In this way, a device can advertise its own information and obtain information about other devices in the network, and finally obtain two MIB libraries that reflect the network topology and other configuration information. These two libraries can be used by their users to perform various functions

LLDP packet:

A packet encapsulated with an LLDPDU is called an LLDP packet. The encapsulation format is two types: Ethernet II and SNAP (Subnetwork Access Protocol).

LLDP packets encapsulated in Ethernet II format:

· Destination MAC address: Destination MAC address, which is a fixed multicast MAC address 0x0180-C200-000E.

· Source MAC address: The source MAC address, which is the port MAC address or device bridge MAC address (if there is a port address, the port MAC address is used, otherwise the device bridge MAC address is used).

· Type: Packet type, which is 0x88CC.

· Data: Data is LLDPDU.

· FCS: Frame check sequence.

LLDP packets encapsulated in SNAP format:

· Destination MAC address: Destination MAC address, which is a fixed multicast MAC address 0x0180-C200-000E.

· Source MAC address: The source MAC address, which is the port MAC address or device bridge MAC address (if there is a port address, the port MAC address is used, otherwise the device bridge MAC address is used).Ccie certification cost.

· Type: Packet type, which is 0xAAAA-0300-0000-88CC.

· Data: Data is LLDPDU.

· FCS: Frame check sequence.

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Ccie certification cost Link layer discovery protocol ( LLDP)explanation(2)

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Ccie certification cost Link layer discovery protocol ( LLDP)explanation

Ccie certification cost Link layer discovery protocol ( LLDP)explanation

 With the development of network technology, there are more and more types of devices accessing the network, and the configuration is more and more complicated. Devices from different device vendors also tend to add their own unique features, which leads to many different features in a network. Ccie certification cost.Devices from different vendors, in order to facilitate the management of such networks, need to enable devices from different vendors to discover and interact with each other's systems and configuration information in the network.

 LLDP (Link Layer Discovery Protocol) is generated in this context, which provides a standard link layer discovery method. The information about the main device, the management address, the device identifier, and the interface identifier of the local device can be organized into different TLV (Type/Length/Value)  and encapsulated in the LLDPDU (Link Layer Discovery Protocol Data Unit)  to be directly connected to the neighbors. Ccie certification cost.After receiving the information, the neighbor saves it in the form of a standard MIB (Management Information Base) for the network management system to query and judge the communication status of the link.

 These MIB information can be used to discover the physical topology of the device and manage configuration information. It should be noted that LLDP is only designed for information advertisement.Ccie certification cost. It is used to advertise information of one device and obtain information of other devices to get related MIB information. Ccie certification cost.It is not a configuration and control protocol. It can't configure the remote device through the protocol. It only provides information about the network topology and management configuration. These information can be used for management, configuration purposes, but how to use it depend on the users.Ccie certification cost.

 In May 2005, this agreement has been recognized as the IEEE802.1AB-2005 standard. It replaces vendor-private protocols such as Cisco's Cisco Discovery Protocol, Extreme Networks' EDP (Extreme Discovery Protocol), Enterasys Networks' CDP (Cabletron Discovery Protocol), and Nortel Networks' NDP ( Nortel Discovery Protocol).

 Simply put, LLDP is a proximity discovery protocol. It defines a standard way for Ethernet network devices, such as switches, routers, and WLAN access points, to advertise their presence to other nodes in the network and to store discovery information for neighboring devices. For example, detailed information such as device configuration and device identification can be announced with this protocol.Ccie certification cost.

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Ccie exam fee A brief look at vxlan technology (4)

Ccie exam fee A brief look at vxlan technology (4)

VXLAN tunnel

 "Tunnel" is a logical concept, it is not new, such as the familiar GRE. To put it bluntly, the original message is "transformed" and "packaged" so that it can be transmitted on a bearer network (such as an IP network). From the perspective of the host, it is as if there is a straight link between the start and end of the original message. Ccie exam fee.And this seemingly straight link is the "tunnel." As the name implies, the "VXLAN tunnel" is used to transmit packets that are encapsulated in VXLAN. It is a virtual channel established between two VTEPs.

The payload message inside VXLAN specified in RFC7348 must be an Ethernet packet, which limits the scope of use of the VXLAN protocol. In order to allow VXLAN to support Overlay transmission of other protocol messages more widely, the RFC draft is exploring VXLAN Generic Protocol Encapsulation (GPE), which is a VXLAN general protocol encapsulation.

   The GPE package uses some of the reserved bits specified in the original FRC7348.

• Version (Ver): Indicates the VXLAN GPE protocol version. The initial value is 0.

• Next Protocol Bit (P bit): If the P bit is 1, the Next Protocol field is valid.

• BUM Traffic Bit (B bit): If the B bit is 1, it indicates that the encapsulated packet in the VXLAN is a BUM packet.Ccie exam fee.

• OAM Flag Bit (O bit): If the O bit is 1, the encapsulated packet in the VXLAN is an OAM packet.

• Next Protocol: 8 digits. Indicates the protocol format of the encapsulated packets inside the VXLAN.

 BUM (Broadcast, Unknown-unicast, Multicast) is broadcast, unknown unicast, and multicast traffic. According to different ways of copying flood traffic, it can be divided into unicast routing mode (head-end replication) and multicast routing mode (core replication). In the head-end replication mode, the VTEP is responsible for copying the packets. The unicast mode sends the copied packets to the local site through the local interface and sends them to all remote VTEPs in the VXLAN through the VXLAN tunnel. After receiving the VXLAN packet, the remote VTEP decapsulates the packet and floods the original data in the VXLAN of the local site. To avoid loops, after the remote VTEP receives a packet from the VXLAN tunnel, it will not flood it to other VXLAN tunnels.

 VXLAN Layer 3 Gateway - L3 Gateway

 The VXLAN Layer 3 gateway provides the Layer 3 forwarding function of the VXLAN. The VXLAN is associated with the VSI virtual interface (VXLAN virtual interface). The VSI virtual interface is assigned the IP address as the gateway of all VMs in the VXLAN.

The main functions of the VXLAN Layer 3 Gateway:

• Realize mutual visits between virtual machines and non-VXLAN networks in VXLAN

• Completing virtual machine exchanges across VXLAN

VXLAN Layer 3 gateways are available in both centralized and distributed modes depending on how they are deployed. 

 Centralized gateways, which are all centered on the Spine device. All traffic across VXLAN, VXLAN and non-VXLAN access traffic need to pass Spine. The advantage of centralized gateway is that all the flows can pass through Spine device, which makes it easier to implement flow control and automatic draining. The disadvantage is that the Spine device is under pressure and is not conducive to large-scale deployment.Ccie exam fee

 In the distributed VXLAN Layer 3 gateway solution, each VTEP device can act as a VXLAN IP gateway to perform Layer 3 forwarding of traffic at the local site. Distributed layer 3 gateway can be a good solution to the problem that leads to excessive pressure in Spine device due to the concentration of traffic. Ccie exam fee.It can also be flexibly extended on the group network. On a distributed gateway network, the Spine device is not a VTEP. It is only part of the Underlay network and is responsible for forwarding ordinary IP packets.

 VXLAN has become the best choice for the current SDN Overlay technology due to its simple data plane and good compatibility, but VXLAN still has a long way to go in the future.

For example, exploring the VXLAN GPE package is a direction, and solving the QoS of the VXLAN tunnel is also a direction. The control plane needs to do more, how to better implement on-demand customization, how to achieve intelligent traffic adjustment, how to better compatible with heterogeneous devices, and so on. Ccie exam fee.I believe that the future will give us a better answer.

 Part of the content is selected from: H3C product support and service technology column "Interpretation of VXLAN"

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 Ccie exam fee A brief look at vxlan technology

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Ccie exam fee A brief look at vxlan technology (3)

Ccie exam fee A brief look at vxlan technology (3) VXLAN communication process: For two virtual terminals in the same VXLAN, the communication process can be summarized as follows: 1. The sender sends a data frame to the receiver, which contains the virtual MAC address of the sender and receiver. 2. The VTEP node connected to the sender receives the data frame. By looking up the VXLAN where the sender is located and the VTEP node to which the receiver is connected, After adding the VXLAN header, the external UDP header, and the external IP header, the packet is sent to the destination VTEP node.ccie exam fee 3. The packet is transmitted over the physical network to the destination VTEP node. 4. After receiving the packet, the destination VTEP node removes the external IP header and the external UDP header of the packet, checks the VNI of the packet, and the destination MAC address of the internal data frame.ccie exam. After confirming that the receiver is connected to the VTEP node, the VXLAN header is removed. Fee.Internal data frames are delivered to the receiver. 5. The receiver receives the data frame and the transfer is complete. VXLAN network model: As you can see from the figure, the following new elements in the traditional data center network appear in the VXLAN network: The edge device of the VXLAN network is the start and end points of the VXLAN tunnel. The related processing of VXLAN packets is performed on this. In short, it is the absolute protagonist in the VXLAN network. The VTEP can be either a network device (such as Huawei's CE series switch) or a server where the virtual machine is located. So how does it work? The answer will be announced later. VNI (VXLAN Network Identifier) As mentioned above, vlans take up only 12 bits of space in Ethernet data frames, which makes the VLAN's isolation capability inadequate in data center networks. The emergence of VNI is specifically to solve this problem. VNI is a user ID similar to VLAN ID. Ccie exam fee.A VNI represents a tenant. Virtual machines belonging to different VNI cannot directly communicate with each other at layer 2. When VXLAN packets are encapsulated, VNI is allocated enough space to support the isolation of massive tenants. Detailed implementation, we will introduce it later.ccie exam fee. Publisher:IE LAB publish Website: http://ielab.network WhatsApp: +8617782638871 Skype:live:ielab.anna Ccie exam fee A brief look at vxlan technology

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ccie certification cost A brief look at vxlan technology (1)

ccie certification cost A brief look at vxlan technology (1) VXLAN is transmitted by encapsulating data frames communicated in a logical network in a physical network. Ccie certification cost .The process of encapsulation and decapsulation is performed by a VTEP node. After VXLAN adds the data frame in the logical network to the VXLAN header, it is encapsulated in the UDP packet in the physical network. • Outer MAC Header: Encapsulates the outer Ethernet header, 14 bytes, or 18 bytes if there is a VLAN TAG. The source MAC address is the MAC address of the VTEP to which the source VM belongs, and the destination MAC address is the MAC address of the next hop device on the path to the destination VTEP. The type field is 0x0800, indicating that the inner layer encapsulates an IP packet.Ccie certification cost . • Outer IP Header: Encapsulates the outer IP header, 20 bytes. The source IP address is the IP address of the VTEP to which the source VM belongs, and the destination IP address is the IP address of the VTEP to which the destination VM belongs. Ccie certification cost .The protocol field is 0x11, indicating that the inner layer encapsulates UDP packets. • UDP Header: UDP header, 8 bytes. The UDP destination port number is fixed to 4789, indicating that the inner layer encapsulated packet is a VXLAN packet. Ccie certification cost .The UDP source port number is a random arbitrary value and can be used for multipath load sharing between VTEPs. • VXLAN Header: VXLAN header newly defined by the VXLAN protocol, 8 bytes • Flags: 8 bits, RRRRIRRR. When the "I" bit is 1, it indicates that the VXLAN ID in the VXLAN header is valid; when it is 0, it indicates that the VXLAN ID is invalid. The "R" bit is left unused and is set to 0. • VXLAN ID (VNI): 24 bit, used to identify a separate VXLAN network. • Reserved: 24 bit and 8 bit, respectively. Reserved bit. • Original L2 Frame: Original Ethernet telegram. As shown in the packet encapsulation, the VXLAN header and the original Layer 2 packet exist as payloads of UDP packets. The network device between the VTEPs needs to be forwarded according to the Outer MAC Header and the Outer IP Header. The UDP Source Port is used for load balancing. This process is identical to forwarding ordinary IP packets. In this way, in addition to the VTEP device, a large number of devices on the live network can support the VXLAN network without replacement or upgrade. However, the newly added VXLAN message encapsulation also introduces a problem, that is, the setting of the MTU value. Generally, the default MTU of a virtual machine is 1500 Bytes, which means that the original Ethernet packet is up to 1500 bytes. When this message passes VTEP, it will encapsulate a new 50-byte header (VXLAN header 8 bytes + UDP header 8 bytes + external IP header 20 bytes + external MAC header 14 bytes), thus the entire message length reached 1550 bytes. On the existing VTEP device, the VXLAN packet cannot be fragmented when the VXLAN packet is decapsulated. Ccie certification cost .Otherwise, the packet cannot be decapsulated correctly. This requires that the MTU of all network devices between VTEPs be a minimum of 1550 bytes. If the MTU value of the intermediate device is not convenient to change, then setting the virtual machine's MTU value to 1450 can also solve this problem temporarily. Publisher:IE LAB publish Website: http://ielab.network WhatsApp: +8617782638871 Skype:live:ielab.anna Ccie certification cost A brief look at vxlan technology (1)

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Ccie certification cost A brief look at vxlan technology (1)

Ccie certification cost A brief look at vxlan technology (1)

VLAN means Virtual Local Area Network, which is the concept involved in the implementation of the switch, defined by the 802.1Q standard. Because the switch is a network device working at the link layer, the terminals connected to the same switch are in the same Layer 3 network and are also in the same broadcast domain. Ccie certification cost.When a switch accesses a large number of terminals, any one of the terminals sends a broadcast packet (for example, an ARP request), and the packet is transmitted throughout the network. For large-scale networking scenarios, the flood of broadcast packets will have a greater impact on network communications. VLAN technology provides a solution to this problem. A VLAN divides the same network into multiple logical virtual subnets. It also stipulates that when a broadcast packet is received, it broadcasts only in its VLAN to prevent broadcast packets from flooding. VLAN technology implements broadcast domain isolation at the link layer level

VXLAN (Virtual eXtensible Local Area Network) is one of the NVO3 (Network Virtualization over Layer 3) standard tecapsulated in a Layer 3 network. The Layer 2 network can be extended in the Layer 3hnologies defined by the IETF. It uses L2 over L4 (MAC-in-UDP) packet encapsulation mode. The Layer 2 packet is enc network and meet the requirements of the data center's large Layer 2 virtual migration and multi-tenancy.

NVO3 is a general term for the technology of building virtual networks based on a three-layer IP overlay network. VXLAN is just one of the NVO3 technologies. In addition, NVGRE and STT are also representative.

Any technology has its own specific background and actual needs. VXLAN is a technology that solves a series of problems in the virtualization of the cloud computing era.

Cloud computing, with its advantages in high system utilization, low manpower/management cost, and flexibility/scalability, has become a new form of enterprise IT construction; in cloud computing, a large number of adoptions And deploying virtualization is a basic technology model.

The extensive deployment of the server virtualization technology greatly increases the computing density of the data center. Ccie certification cost .At the same time, in order to achieve flexible service changes, the virtual machine VM (Virtual Machine) needs to be able to migrate without restriction in the network (as shown in Figure ). In fact, for data centers, virtual machine migration has become a normal business.

Virtual machine migration, as its name implies, is the migration of virtual machines from one physical machine to another,However, the business cannot be interrupted during the migration process. Ccie certification cost .To do this, you need to ensure that the parameters such as the IP address and MAC address remain unchanged before and after the virtual machine is migrated. This determines that virtual machine migration must occur in a Layer 2 domain. The second-tier domain of the traditional data center network limits virtual machine migration to a smaller local area.

You can build a physical large Layer 2 network through stacking, SVF, TRILL, and other technologies.it can expand the scope of virtual machine migration. Ccie certification cost .However, building a physical large layer 2 will inevitably require major changes to the original network, and the scope of the large layer 2 network will still be limited by various conditions. Ccie certification cost .As a result, VXLAN emerged under the joint promotion of world-renowned manufacturers such as VMware and Cisco.

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 Ccie certification cost A brief look at vxlan technology (1)

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Ccie lab dumps Introduction to SPAN and RSPAN for port mirroring(1)

Ccie lab dumps Introduction to SPAN and RSPAN for port mirroring(1)

 SPAN technology is mainly used to monitor the data flow on the switch, which is roughly divided into two types, Local Switched Port Analyzer (SPAN) and Remote SPAN (RSPAN), the implementation method is slightly different. With SPAN technology, we can COPY or MIRROR the data stream of some ports on the switch that we want to be monitored.ccie lab dumps.Send to the traffic analyzer connected to the destination Port , such as CISCO IDS or PC with SNIFFER tool. The Source Port and destination Port can be on the same switch (local SPAN) or on different switches ( Remote SPAN).

SPAN, known as Switched Port Analyzer, it is a port mirroring technology for switches. The main purpose is to provide network data flow to a certain network analyzer. Ccie lab dumps.SPAN does not affect the data exchange of the source port. It simply sends a copy of the packet sent or received by the source port to the destination Port .

RSPAN (Remote SPAN), which is similar to SPAN, provides remote monitoring of multilayer switches across a switched network.

1. SPAN Session

A SPAN session is a flow of data between a set of 1. Source Ports and a destination port. It can monitor the incoming traffic of multiple ports or the outgoing traffic of one port at the same time, and can also monitor the incoming traffic of all ports in the VLAN, but cannot simultaneously go out to multiple ports.

Traffic and VLAN outbound traffic are monitored, you can set SPAN on a port that is down. but the SPAN session is inactive at this time.

But as long as the relevant interface is opened, SPAN becomes active.

The destination Port is preferably >= Source Port bandwidth, otherwise packet loss may occur.

2. SPAN Traffic

Use local SPAN to monitor all network traffic, including multicast, bridge protocol data unit (BPDU), and CDP, VTP, DTP, STP, PagP, and LACP packets. RSPAN cannot monitor Layer 2 protocols.

2. Traffic Types 

There are three types of traffic being monitored, Receive (Rx) SPAN Source Port receive traffic, Transmit (Tx) SPAN Source Port transmit traffic, and Both a Source Port receive and send traffic.

SPAN port type

1. Source Port--SPAN source port, also called monitored port

The Source Port can be the actual physical port, VLAN, or Ethernet channel. The physical port can be in different VLANs. If the Source Portis a VLAN, all the physical ports in the VLAN are included. If the Source Port is an Ethernet channel, Then includes all the physical ports that make up this EtherChannel. If the Source Portis a trunk port, all VLAN traffic carried on the trunk port will be monitored. You can also use the filter vlan parameter to adjust only the VLAN data traffic specified in the filter vlan.

2. Destination Port--SPAN, which is the monitoring Port (for monitoring equipment).

A destination Port can only be a single physical port. A destination Port can only be used in one SPAN. The destination Port does not participate in other Layer 2 protocols.ccie lab dumps.

Cisco Discovery Protocol (CDP),

VLAN Trunk Protocol (VTP),

Dynamic Trunking Protocol (DTP),

Spanning Tree Protocol (STP),

Port Aggregation Protocol (PagP),

Link Aggregation Control Protocol (LACP) and so on

By default, the destination Port does not forward any data stream except the SPAN Session. You can also enable the Layer 2 forwarding function of the destination Port by setting the ingress parameter. For example, there is such a need when connecting CISCO IDS. Ccie lab dumps.At this time, the IDS not only needs to receive the data stream of the SPAN Session, but the IDS itself also has communication traffic with other devices in the network, so you need to open the Layer 2 forwarding function of the destination Port. The bandwidth of the destination Port is preferably greater than or equal to the bandwidth of the controlled port. Otherwise, packet loss may occur.

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Cisco ccie exam Linux overview and history

Cisco ccie exam Linux overview and history

Simply put, the Linux operating system is a clone of the UNIX operating system, which was born on October 5, 1991 (the first time it was officially announced). It's the same as Microsoft's Windows, apple's MAC OS and android on mobile phones. Cisco ccie exam.Compared to ordinary people, Linux system may be relatively unfamiliar, and most of them are probably familiar with Windows system. Since the graphical interface of Windows is simpler and easier to use, Windows occupies more markets, and Linux systems are mainly command-line operations, which are more demanding for professionalism.Cisco ccie exam

Linux systems are stable, secure, and have strong concurrency, so they are widely used in the server field. The professional servers are almost all Linux systems. Linux is open source, free, everyone can see the source code of Linux, you can use Linux for free. And the Linux kernel is short and lean, and some can only be a few hundred K in size after being streamlined. Moreover, the Linux kernel is short and succinct, and some can only be a few hundred K in size after being streamlined. Cisco ccie exam.Therefore, it is large enough for PCs and supercomputer operating systems independently developed by countries, and small to the car system, smart devices, the Internet of things on the basic use of the Linux kernel, such as android is the Linux kernel

The birth, development and growth of the Linux system has always depended on the following five important pillars: UNIX system, MINIX system, GUN project, POSIX standard and Internet network.

Speaking of the origin of the Linux system, we have to start with the UNIX system.

The UNIX operating system was a time-sharing operating system developed by Ken.Thompson and Dennis Ritchie of Bell Labs in the United States on the DEC PDP-7 compact computer in the summer of 1969. At that time, the BCPL language was used, and later it was rewritten using the C language, so that the UNIX system was widely used.Cisco ccie exam

The GNU Project was launched in 1984 by the famous hacker Richard Stallman. GNU is supported by the FSF for Free Software Foundation, which is the main source of funding for GNU. The purpose is to build a free UNIX system. Cisco ccie exam.The basic principle is to share source code and share ideas. Create a completely free operating system, except for hardware, like the operating system kernel, the shell of the operating kernel, and the various software should be free.

The GUN Project requires a free open source operating system kernel. It was written by Linus Torvalds, Linux was released by Linus Torvalds at the University of Helsinki in Finland in October 1991. Linux is arguably a clone of the UNIX operating system.

Many companies or communities organize the kernel, source code, and related applications into a complete operating system, making it easy for the average user to install and use Linux. This is the so-called distribution. For example, we often say REDHAT.

Linux distribution:

Strictly speaking, Linux is just the name of the kernel. Organizations and individuals continue to add various system software and applications on the basis of the kernel, and then release them into various distributions, such as Ubuntu, Redhat, CentOS, Fedora, red flag Linux, deepin and so on. Among them, Ubuntu does a better job in the graphical interface, and CentOS is widely used on the server. Cisco ccie exam.In addition, both redhat and CentOS are from Red Hat, redhat is a paid version, and CentOS is a version that Red Hat contributes to the open source community.

Features:

1. Linux system is free, it is the essence of countless programmers around the world, and it is growing.

2. Multi-user, multi-tasking system. Not affected by each other.

3. Good user interface, text interface and graphical interface.

4. Support multiple file systems

5. A variety of network features.

6. Reliable system security.

7. Good portability.

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Cisco ccie exam Linux overview and history

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cisco ccie exam 5G and WIFI6, still can't tell? (1)

cisco ccie exam 5G and WIFI6, still can't tell? (1) Ⅰ. the opening: On October 3, 2018, the Wi-Fi Alliance officially incorporated WiFi based on the 802.11ax standard into the regular army and became the sixth generation WiFi technology. The WiFi specification was renamed, the standard 802.11n was renamed to WiFi 4, the standard 802.11ac was renamed to WiFi 5, and the new standard 802.11ax was renamed to WiFi 6. (Of course, the previous generation of 802.11b/a/g can be chased as WiFi 1/2/3) Not only changed the naming convention of WiFi, but also in the network connection of WiFi devices. Also all use the new UI icon. The icon will display the level of the WiFi network you are currently connected to through the most intuitive numbers. Wi-Fi is well known to us. Wi-fi has evolved from 802.11b in 1999 and has gone through five generations. The Wi-Fi Alliance announced the simplification of the name of the new Wi-fi to Wi-fi6 when it introduced the new generation of 802.11ax standards. cisco ccie exam .After all those years, the Wi-Fi Alliance finally opened up. It is much better to use the size of the number to standardize the WiFi specification. Finally, you can recommend the latest products to your friends without explaining the complicated specifications. So what is WiFi 6? What's so good about WiFi 6(11ax)? Ⅱ.what is WiFi 6? Wi-Fi 6 is based on the new IEEE 802.11ax standard, so these two terms may be interchanged. Converted Wi-Fi version: Wi-Fi 1 is 802.11b released in 1999. Wi-Fi 2 is 802.11a and also released in 1999. Wi-Fi 3 is 802.11g released in 2003. Wi-Fi 4 is 802.11n and was released in 2009. Wi-Fi 5 is 802.11ac released in 2014. Wi-Fi 6 is a new version, also known as 802.11ax. Ⅲ, the difference between WiFi4 WiFi5 WiFi6 WiFi 4 802.11n was out in 2009. With 40MHz bandwidth and MIMO black technology, it upgraded the WiFi theoretical bandwidth from 54Mbps at 11a/g to 600Mbps (150Mbps×4 spatial streams), and 11n supports 2.4G/5G band at the same time. Perfectly replace the old standard. WiFi 5 That is, 802.11 ac, was out in 2013. The original version (Wave 1) boosted WiFi single-stream bandwidth to 433Mbps with 80MHz bandwidth. The second edition of 2016 (Wave 2) draws on the characteristics of part 11ax and doubles the bandwidth to 160MHz. Although 11ac theoretically supports 8 spatial streams, it basically only achieves 4×4 (80MHz) or 2×2 (160MHz) in the home WiFi market, that is, the theoretical bandwidth is 1733Mbps, which is very different from the 11ac limit bandwidth (6.9Gbps). cisco ccie exam.But because wireless network transmission is based on wired networks. Therefore, the current mainstream of the family is the background of the Gigabit network. WiFi 5 did not become a network bottleneck. It is worth noting that 11ac only supports the 5G band. Therefore, it is technically impossible to replace 11n supporting the 2.4G frequency band. Current mainstream home wireless routers can only choose to support both WiFi 4 and WiFi 5. Therefore, WiFi 5 is an upgrade iteration of WiFi 4, which is somewhat less rigorous. WiFi 6 Based on 802.11 ax technology, this technology is strictly in the womb. The draft is still under discussion and is expected to be officially standardized in 2019. However, most of its technical specifications have been made public, so some manufacturers have made the specification into products to grab the market.cisco ccie exam. 11ax supports the 2.4G/5G band at the same time, which is the sixth generation WiFi iteration standard in the true sense. The 11n and 11 ac products on the market will be replaced in the future. In addition, 11ax also brings a complete version of mu-mimo, supporting 8 terminals uplinking/downlink mu-mimo, and introducing OFDMA black technology to realize another parallel transmission capacity complementary to mu-mimo, which is more flexible and practical than mu-mimo. Publisher:IE LAB publish Website: http://ielab.network WhatsApp: +8617782638871 Skype:live:ielab.anna