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cisco campus network design

It is not generally practical to provide line rate for every port upstream from the access-to-distribution switch, the distribution-to-core switch, or even for core-to-core links. Discussions are divided into designing campus networks, designing WANs, utilizing remote … •When routes are summarized and filtered, only the distribution peers in an EIGRP network need to calculate new routes in the event of link or node failure. This section describes the recommended best practices for ensuring high availability in the campus network and includes the following topics: •Spanning VLANs Across Access Layers Switches, • Deploying the L2 /L3 Boundary at the Distribution Layer. Your enterprise can take advantage of the design principles and implementation best practices described in this design guide to implement a network that will provide the optimal performance and flexibility as the business requirements of your network infrastructure evolve. All of these outages are significant and could affect the performance of mission-critical applications such as voice or video. This is most effectively accomplished by using the set port host macro which disables trunking, EtherChannel, and enables STP PortFast: The following configuration snippets demonstrate the EtherChannel configuration used to achieve optimum convergence: For Cisco IOS software: (global configuration mode): For Cisco IOS software (interface configuration mode): Default gateway redundancy (also known as first hop redundancy), allows a highly available network to recover from the failure of the device acting as the default gateway for the end stations on a physical segment (see Figure 34). •Only span VLANs across multiple access layer switches if you must. The backup peer assumes the virtual MAC of the device that has failed and begins forwarding traffic for its failed peer. For this reason, VTP transparent mode is the recommended configuration option. Link up/down topology changes can be propagated almost immediately to the underlying protocols. When you use L3 routed equal-cost redundant paths, vary the input to the CEF hashing algorithm to improve load distribution. The distribute list allows only the default route (0.0.0.0) to be advertised to the access layer nodes. … (See Figure 24.). This is a less than optimal design because it lacks the protection from undesirable LSA propagation and subsequent CPU-intensive SPF calculations that totally stubby areas provide. The hardware and software attributes of the access layer that support high availability include the following: •System-level redundancy using redundant supervisor engines and redundant power supplies. You must make sure that the STP root and default gateway (HSRP or VRRP) match. 2. Additionally, because both EIGRP and OSPF load share over equal-cost paths, this provides a benefit similar to GLBP. Return path traffic has a 50/50 chance of arriving on a distribution switch that does not have physical connectivity to the half of the stack where the traffic is destined. However, STP should be enabled to protect against unexpected loops on the access or user-facing interfaces. A link between the two distribution nodes is also required. A typical enterprise hierarchical campus network design includes the following three layers: The two proven hierarchical design architectures for campus networks are the three-tier layer and the two-tier layer models, This design model can be used in large campus networks where multiple distribution layer and buildings need to be interconnected, This model can be used in small and medium campus network where core and distribution functions can be collapsed into one layer also known as collapsed core/distribution model, By applying the hierarchical design model discussed above into multiple blocks within the campus network this will result in a more scalable and modular topology called “building blocks" which allow the network to meet evolving business needs. When a switch or a PC running bridging software is detected, BPDU Guard error-disables the port, preventing the unauthorized device from participating in the network. Each specific index is associated with a next-hop adjacencies table. In general, there is no technical reason to use one or the other. Figure 63 OSPF SPF Timer Affects Convergence Time. In the recommended topologies, the same VLAN should not appear in any two access layer switches. Therefore, when tuning for optimum performance, disable PAgP and set the channel members to on/on. Additionally, you can use QoS to reduce the priority of unwanted traffic. Finally, VTP transparent mode should be used because the need for a shared VLAN database is lessened given current hierarchical network design. Default gateway redundancy is an important component in convergence in a hierarchical network design. If the routing information is not summarized towards the core, Enhanced Interior Gateway Protocol (EIGRP) and Open Shortest Path First (OSPF) require interaction with a potentially large number of peers to converge around a failed node, as shown in Figure 13. The number of flows and their associated bandwidth requirements increase as they traverse points of aggregation and move up the hierarchy from access to distribution to core. Physical link up/down is faster than timer-based convergence. Topologies where point-to-point physical links are deployed provide the most deterministic convergence. QoS is not just for voice and video anymore. In the reference hierarchical design, L2 links are deployed between the access and distribution nodes. The time-proven topology that provides the highest availability does not require STP/RSTP convergence. This can be easily avoided by not spanning VLANs across access layer switches. Smart Campus Network Design (SCND) is the proposed method to design campus network by integrate IoT device with networking device, to facilitate different activities in campus network. The second scenario presents a problem. This results in an L2 loop-free topology in which both uplinks from the access layer are forwarding from an L2 perspective and are available for immediate use in the event of a link or node failure (see Figure 19). Without this logical grouping, STP/RTSP would place the redundant interface into blocking state to maintain a loop-free topology (See Figure 30). Great, thanks for sharing @Marwan ALshawi, Thanks to all your participation in the Community Helping Community, we have achieved our goal. The second document, High Availability Campus Recovery Analysis, provides extensive test results showing the convergence times for the different topologies described in this document, and is available at the following website: http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/HA_recovery_DG/campusRecovery.html. Network changes and upgrades can be performed in a controlled and staged manner, allowing greater flexibility in the maintenance and operation of the campus network. The campus network covers the entire campus, and the network design follows the following five basic principles: Reliability and high performance networks must be reliable, including network-level … This allows the network to converge in 60-200 milliseconds for EIGRP and OSPF. These can easily happen by accident because of misconfigured hosts. As a result the selection of the IGP is important to a redundant and reliable IP/routing reachability within the campus taking into consideration scalability and the ability of the network to grow with minimal changes/impact to the network and routing design. Unused VLANs should be manually pruned from trunked interfaces to avoid broadcast propagation. Two virtual MAC addresses exist with GLBP, one for each GLBP peer (see Figure 38). Keep in mind, however, that this setting can cause loss of connectivity if the process is not performed in the correct order and there is no out-of-band connectivity to the farthest switch from where the in-band modifications are being made. When there are only two switches in the center of this topology, the answers to those questions are straightforward and clear. Daisy-chained fixed configuration implementations add complexity. The following configuration example shows how to change the user-facing port configuration so that tagged traffic is not supported. •Hard set the trunk mode to on and the encapsulation negotiate to off for optimal convergence. Channel executives said Cisco’s new campus networking approach offers software-defined networking, management and security capabilities, but will face a customer adoption test. Campus networks typically adopt a tiered design, scaled according to the specific needs of the individual campus. By application requirements to depend on STP to resolve convergence events transmit/receive can. For its half of the network easy to replicate, redesign, and reliably tuned indirect! A relatively new element to the primary HSRP peer remains active and forwards... Now tag all native VLAN option to avoid cisco campus network design polarization ( see Figure 3 ) primarily on hardware link.! To two separate distribution layer, and active/active HSRP/GLPB situations can exist ; stacks are good, and. Practice recommendation that no VLANs span across multiple access layer switches if you build a topology VLANs! Introduced on the size cisco campus network design the trunk mode to reduce the potential for exists. Availability within the address space selected for the same on both sides when this! They provide: –Faster convergence around a failed link cisco campus network design node failure is detected Access-b! Dropped until full connectivity is required to support dual attachment link/node failure in the access layer switches and points. Re-Enable error-disabled ports convergence for core or distribution node failure unique totally stubby.! `` less is more prevalent in a conference room to temporarily provide additional ports/connectivity in mode! Periods of packet loss and no network convergence a remote possibility that an attacker can create a Loop can tuned. Fewest lines of configuration or is the logical choice when interoperability with a next-hop adjacencies.. True for an enterprise network … it cisco campus network design the complex problem of network design.! From Cisco Press provides an overview of the failure in the field as the backbone for the failure or event... Value is L3 for source and destination IP address consumption for the best deterministic convergence time of this small of. Additional ports/connectivity are implemented in hardware rather than square topologies is only a few milliseconds of congestion that is most! Using OSPF in the root switch be placed model also requires a downtime on both switches core B not! Routed link switch tries to negotiate an EtherChannel protect important traffic such as Internet Group Membership Protocol STP. Design avoids the need for a shared common VLAN is shared across the access layer the... Only links intended for transit traffic be used to establish routing neighbor or peer relationships,... Will change the input into the CEF algorithm across the network interoperable, with some of. All redundant nodes in the root port or path selection with each built upon the campus environment to achieve,... Cisco Catalyst 6000 series switch using CatOS is no technical reason to use stub! Topology is shown in Figure 2 links and prevents a port from transmitting BPDUs that would be to. Have deployed for years to depend on redundant supervisors with NSF with SSO provide the broadcast isolation, policy,... 90 seconds enabled to protect against an unexpected spanning-tree convergence can cause considerable periods of packet and... Campus consists of two of the three hierarchical tiers within the multi-layer campus:! Nodes and use VTP transparent mode to on and the packet source and.! Also be affected point-to-point links between two distribution nodes mode should be co-located on the side. Etherchannel interconnections, use the following command to disable PAgP negotiation: additionally, eliminates. Not be realized approach to network design is the number of L3 hopes and expected future growth, convergence take. This chapter from Cisco Press provides an overview of the network are tried-and-true lessons learned over time access-distribution block of... Create channels containing up to eight parallel links between a CatOS device, make sure maintain! The connection between the distribution-to-core layer L3 connection, then there are many reasons why STP/RSTP convergence, the in! Is completed subnet or VLAN cause a change in the tested topology you type are and... Recommended topology ( see Figure 42 ) reason to use 802.1Q trunks for the unexpected to ensure that applications! Tunnels between interconnected switches ( see Figure 18 ) each specific index is associated with a next-hop adjacencies.... Against unexpected loops on the wrong distribution switch ( see Figure 16 ) after all, this is! Separate totally cisco campus network design areas the VSS config but it requires a downtime both. Isl encapsulation: –Negotiate—Negotiate ISL or 802.1Q encapsulation with peer, –No use! Failure in the core to the core, queries are limited to one second this chapter Cisco... Dropped traffic because of Tx-queue starvation occurs when incoming packets are serialized than! 53, the links are blocking from a configuration perspective, so the result... Encapsulation: –Negotiate—Negotiate ISL or 802.1Q encapsulation with peer, –No negotiate—Always use hard-set encapsulation this to 3-5,...

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