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CEF Changing Structures around the Cisco Catalyst 6500 On the SUP720, 'cisco' Catalyst 6500 uses CEF, which cannot be handicapped, to provide equipment effectiveness. Instead of performing changing within software as previous 'cisco' hubs do, the actual 'cisco' Catalyst 6500 works changing in equipment utilizing CEF. You need to understand this difference when trouble shooting problems involving a SUP720.

Knowing Software-Based CEF as well as Hardware-Based CEF Hardware-based CEF packet changing leverages the present data structures built by CEF within software and then extends the capability in order to equipment by programming specific hardware memories along with info the sending ASICs can use to rapidly transfer packages with regard to improved performance. Within software-based CEF, the actual router builds the Forwarding Info Base (FIB) and adjacency furniture in line with the redirecting as well as Deal with Quality Process (ARP) tables. The Driver 6500 change stores these details within hardware high-speed desk memory and uses effective research algorithms for table searches. Within the Catalyst 6500, these types of high-speed memory tables tend to be Ternary Content material Addressable Memory (TCAM) tables. TCAM uses a combination of value matching having the ability to cover up for a particular result. In this case, the result is a pointer for an admittance within the equipment adjacency desk which has the actual next-hop Macintosh rewrite information.

The SUP720 lists FIB entries in the TCAM table in the most specific towards the minimum specific entry. Therefore, the TCAM listings all records with a subnet mask associated with Thirty-two (host admittance) for a particular prefix first. When the FIB and adjacency tables in the TCAM tend to be full, the SUP720 punts traffic for that unfound destination/entry towards the software-switching motor (path processor, or even RP) to become dealt with in software. The actual SUP720 has an integrated RP and change processor chip (SP) around the Multilayer Switch Feature Greeting card Three (MSFC3). The actual SP handles common Coating 2 capabilities for example Comprising Sapling and VLAN Trunking. The RP deals with typical Coating 3 functions such as Enhanced Interior Entrance Redirecting Process (EIGRP) as well as redirecting.

The SUP720 also offers a Policy Feature Greeting card Three (PFC3) to support hardware-based sending featuring such as routing, multicast box duplication, and access control listings (ACLs). Multiple PFC3s, such as the PFC3B and the PFC3BXL, are available. On a SUP720 having a PFC3BXL, the actual FIB TCAM dimension and also the adjacency desk size is 1 million records. The type of functions enabled can impact the number of TCAM entries the SUP720 uses to store information. Every Internet protocol version 4 (IPv4) destination prefix known takes one admittance in the TCAM. Consequently, the PFC3BXL edition facilitates a lot of IPv4 routes as well as adjacencies that can be contained in a sizable enterprise or company network. Nevertheless, with IPv6 as well as ingress multicast paths, every destination takes two records within the TCAM. Refer to 'cisco'.com for that latest information related to whether an element influences the entire quantity of entries stored in TCAM.

The SUP720 pushes software program CEF information right down to the actual hardware The company, which could manage the actual box forwarding quicker. The RP on the SUP720 transmits the data to the SP in order to plan the actual TCAM and the hardware The company.

Hardware FIB lookup happens based on the greatest matching location prefix. A complement in the equipment FIB in line with the destination prefix returns adjacency information that contains the box rewrite information for the correct outgoing user interface. Then, forwarding of the packet happens to the next jump in equipment. Observe that prior to the Cisco Driver 6500 passes the box outgoing, additionally, it validates protection and quality of support (QoS) guidelines to verify that the packet is lawful and cannot end up being fallen instead.

Centralized as well as Dispersed Switching The actual Cisco Catalyst 6500 facilitates centralized changing or distributed switching. Central switching takes place when the change processor chip on the SUP720 can make sending decisions within hardware. All frames must pass through the central SP motor by the change fabric or bus. Coach as well as crossbar switching settings use the centralized SP.

Along with use of the Dispersed Sending Cards (DFCs) on the line segments, distributed changing can occur. With distributed changing, forwarding occurs in your area on the line modules which bypass the centralized switching engine on the supervisor engine, as well as packages tend to be submitted straight between two ports or over the switch fabric.

In the event that traffic is ingress on the greeting card that is DFC outfitted, the DFC performs the hardware switching for your collection greeting card. Therefore, you need to check the hardware CEF entries on the DFC itself whenever troubleshooting. You should use the display material switching-mode command to check regardless of whether the line greeting card is DFC equipped. When the result says "DCEF" (showing distributed CEF [dCEF]) under changing setting, it has a DFC. 9131252012wed

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