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CEF Switching Architecture around the 'cisco' Catalyst 6500 Around the SUP720, Cisco Driver 6500 uses CEF, that cannot be disabled, to provide equipment effectiveness. Rather than carrying out changing within software because prior 'cisco' hubs did, the actual Cisco Driver 6500 works changing in equipment utilizing CEF. You must know this particular distinction whenever trouble shooting problems involving a SUP720.

Understanding Software-Based CEF as well as Hardware-Based CEF Hardware-based CEF box changing harnesses the present data structures constructed by CEF in software after which extends the ability in order to hardware through encoding specific hardware memories with information that the forwarding The company may use to quickly transfer packages for enhanced performance. Within software-based CEF, the router builds the actual Sending Info Base (FIB) as well as adjacency furniture in line with the routing and Address Quality Process (ARP) tables. The Catalyst 6500 switch stores these details in hardware high-speed desk memory and uses efficient research calculations with regard to desk lookups. Within the Driver 6500, these types of high-speed memory furniture tend to be Ternary Content material Addressable Storage (TCAM) furniture. TCAM utilizes a combination of value matching having the ability to mask for a particular result. In this instance, the result is the tip to an entry within the equipment adjacency desk which has the actual next-hop Macintosh rewrite information.

The SUP720 listings FIB entries in the TCAM desk in the the majority of specific towards the least specific admittance. Therefore, the actual TCAM lists just about all entries having a subnet mask of Thirty-two (host admittance) for a particular prefix very first. Once the FIB and adjacency furniture within the TCAM are complete, the SUP720 punts visitors for the unfound destination/entry to the software-switching engine (route processor chip, or RP) to become handled in software. The SUP720 has an integrated RP as well as switch processor (SP) on the Multilayer Switch Feature Greeting card Three (MSFC3). The SP deals with typical Coating Two functions for example Spanning Sapling as well as VLAN Trunking. The RP handles typical Layer Three functions for example Improved Interior Gateway Routing Process (EIGRP) and routing.

The actual SUP720 also offers a Policy Feature Card Three (PFC3) to aid hardware-based sending featuring for example redirecting, multicast packet replication, and access control lists (ACLs). Multiple PFC3s, like the PFC3B and also the PFC3BXL, can be found. On a SUP720 having a PFC3BXL, the FIB TCAM size and the adjacency desk dimensions are A million entries. The kind of functions allowed can impact the amount of TCAM entries that the SUP720 utilizes to keep info. Every Internet protocol edition Four (IPv4) destination prefix known requires one admittance within the TCAM. Therefore, the actual PFC3BXL version supports a large number of IPv4 paths as well as adjacencies that may be contained in a sizable enterprise or even company network. However, with IPv6 as well as ingress multicast routes, every destination takes 2 entries within the TCAM. Make reference to Cisco.org for the latest information associated with whether a feature impacts the total quantity of entries stored in TCAM.

The actual SUP720 pushes software CEF information right down to the actual equipment ASICs, which could handle the box sending faster. The actual RP around the SUP720 sends the data towards the SP in order to plan the actual TCAM and also the equipment ASICs.

Equipment FIB lookup happens in line with the greatest matching location prefix. A match within the hardware FIB in line with the location prefix results adjacency information which has the actual box rewrite info for that correct outbound user interface. After that, sending from the packet happens to another jump in equipment. Observe that before the 'cisco' Driver 6500 passes the actual packet outgoing, additionally, it validates security and quality of service (QoS) guidelines to confirm the packet is actually lawful and cannot end up being fallen rather.

Centralized as well as Distributed Switching The actual Cisco Catalyst 6500 supports central switching or distributed changing. Centralized changing takes place when the switch processor chip around the SUP720 can make sending decisions in equipment. Just about all frames should go through the actual central SP motor through the change fabric or coach. Coach and crossbar changing settings use the centralized SP.

Along with use of the Dispersed Forwarding Cards (DFCs) on the line segments, dispersed changing can happen. Along with distributed switching, sending happens locally on the line segments that avoid the centralized switching motor around the boss engine, as well as packets tend to be forwarded directly between two plug-ins or over the switch material.

If visitors are ingress on the card that's DFC outfitted, the DFC performs the hardware changing for that line card. Consequently, you have to check the equipment CEF entries around the DFC by itself when trouble shooting. You should use the actual display material switching-mode order to check on whether a collection greeting card is actually DFC equipped. When the result says "DCEF" (showing dispersed CEF [dCEF]) under changing setting, it has a DFC. 9131252012wed

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