[c-nsp] Sup2T-XL vs Sup720BXL FIB TCAM

Jon Lewis jlewis at lewis.org
Tue Nov 5 11:18:50 EST 2013


Your paste formatting got all screwy, but it looks like the Sup2TXL claims 
it can do both 1M v4 routes _and_ half a million v6 routes simultaneously. 
I've heard that from others, but also read the specs to be the same as the 
3BXL.  I wonder if anyone from cisco can shed some light on this?

On the Sup2T-XL, had you done any mls cef maximum-routes tuning?  The page 
below both states that the PFC4XL has no more FIB capacity than the 
PFC3XL, and that the default split on the PFC4XL is 512k IPv4 routes. 
This doesn't appear consistent with what you're seeing.

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/white_paper_c11-676346.html

The FIB in the PFC4 contains 256 K entries, while the FIB in the PFC4XL 
contains 1 million entries. These are the same as their PFC3x forwarding 
engine counterparts. The FIB in the PFC4 contains prefix entries for IPv4 
and IPv6 global address, IPv4 and IPv6 multicast addresses and MPLS label 
entries. There is a level of partitioning that exists to ensure there is 
always some space available for different types of forwarding entries. 
There is some flexibility from a user configuration standpoint that allows 
these partition boundaries to be changed to accommodate more of one type 
of forwarding entry. For example, in the PFC4XL, the default setting 
provides for 512 K IPv4 entries, and this can be increased through 
configuration control to support up to 1 M entries if required.

On Tue, 5 Nov 2013, Christian Schmit wrote:

>
> Today I tested a Sup2T-XL and a Sup720BXL in the lab with full bgp feeds for ipv4 and ipv6.
> To my understanding the hardware capacity for the FIB TCAM is the same for Sup720-BXL and Sup2T-XL.
> Sup2T-XL output of "sh platform hardware capacity":CAT6500-RC2TXL#sh platform hardware capacity | begin L3 Forwarding Resources
> L3 Forwarding Resources              FIB TCAM usage:                         Total           Used         %Used                   72 bits (IPv4, MPLS, EoM)     1048576      465980       44%                  144 bits (IP mcast, IPv6)         524288       14903          3%                  288 bits (IPv6 mcast)               262144           1            1%
>                      detail:      Protocol                    Used       %Used                                   IPv4                          465978       44%                                   MPLS                            1          1%                                   EoM                              1          1%
>                                   IPv6                        14894          3%                                   IPv4 mcast                     9          1%                                   IPv6 mcast                     1          1%
>             Adjacency usage:                     Total        Used       %Used                                                        1048576       32018          3%
>
> Sup720BXL output of "sh platform hardware capacity": (FIB TCAM partitioned with "mls cef maximum-routes ip 768")
> CAT6500-RC720BXL#sh platform hardware capacity | begin L3 Forwarding Resources
>
> L3 Forwarding Resources
>             FIB TCAM usage:                          Total        Used       %Used
>                  72 bits (IPv4, MPLS, EoM)       802816      467348         58%
>                 144 bits (IP mcast, IPv6)           122880       14970         12%
>
>                     detail:      Protocol                    Used       %Used
>                                  IPv4                           467338       58%
>                                  MPLS                             9          1%
>                                  EoM                               1          1%
>
>                                  IPv6                           14963         12%
>                                  IPv4 mcast                       4          1%
>                                  IPv6 mcast                       3          1%
>
>            Adjacency usage:                     Total        Used       %Used
>                                                        1048576        1481          1%
>
> The release notes say:
>
> -XL mode:
>
> · IPv4 and MPLS: Up to 1,007,000 routes
> · IPv4 multicast and IPv6 unicast and multicast: Up to 503,000 routes
>
> "These are the theoretical maximum numbers of routes for the supported protocols (the maximums are not supported simultaneously):"
>
> The above output of the Sup2T-XL seems to say that the Sup2T-XL has a larger FIB TCAM (2M) than the Sup720-BXL.
>
> Christian
>
>
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----------------------------------------------------------------------
  Jon Lewis, MCP :)           |  I route
                              |  therefore you are
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