FW: Getting pretty close to default IPv4 route maximum for 6500/7600routers.

John van Oppen jvanoppen at spectrumnet.us
Mon Jun 9 19:38:15 UTC 2014

Yep, exactly… the problem is the carving suggested by most kills the fact that MPLS and v4 are pooled, which on a larger network is very nice, especially if using 6PE where each v6 route may need an MPLS route too.

From: Bryan Tong [mailto:contact at nullivex.com]
Sent: Monday, June 09, 2014 12:37 PM
To: John van Oppen
Cc: nanog at nanog.org
Subject: Re: FW: Getting pretty close to default IPv4 route maximum for 6500/7600routers.

John, great point!

Regardless, shouldn't need more than 626K to make it to v6 and we wont need as many for v6. That was one of the problems that v6 was designed to address.

On Mon, Jun 9, 2014 at 1:27 PM, John van Oppen <jvanoppen at spectrumnet.us<mailto:jvanoppen at spectrumnet.us>> wrote:
It is generally much better to do the following:

mls cef maximum-routes ipv6 90
mls cef maximum-routes ip-multicast 1

This will leave v4 and mpls in one big pool, puts v6 to something useful for quite a while and steals all of the multicast space which is not really used on most deployments.

This gives us the following (which is pretty great for IP backbone purposes in dual stack):

#show mls cef maximum-routes
FIB TCAM maximum routes :
Current :-
 IPv4 + MPLS         - 832k (default)
 IPv6                - 90k
 IP multicast        - 1k


-----Original Message-----
From: NANOG [mailto:nanog-bounces at nanog.org<mailto:nanog-bounces at nanog.org>] On Behalf Of Jon Lewis
Sent: Monday, June 09, 2014 12:10 PM
To: Pete Lumbis
Cc: nanog at nanog.org<mailto:nanog at nanog.org>
Subject: Re: Getting pretty close to default IPv4 route maximum for 6500/7600routers.

Why, in your example, do you bias the split so heavily toward IPv4 that the router won't be able to handle a current full v6 table?  I've been using

mls cef maximum-routes ip 768

which is probably still a little too liberal for IPv6

FIB TCAM maximum routes :
Current :-
  IPv4                - 768k
  MPLS                - 16k (default)
  IPv6 + IP Multicast - 120k (default)

given that a full v6 table is around 17k routes today.

A more important question though is how many 6500/7600 routers will fully survive the reload required to affect this change?  I've lost a blade (presumably to the bad memory issue) each time I've rebooted a 6500 to apply this.

On Mon, 9 Jun 2014, Pete Lumbis wrote:

> The doc on how to adjust the 6500/7600 TCAM space was just published.
> http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-serie
> s-switches/117712-problemsolution-cat6500-00.html
> On Tue, May 6, 2014 at 3:48 PM, Pete Lumbis <alumbis at gmail.com<mailto:alumbis at gmail.com>> wrote:
>> There is currently a doc for the ASR9k. We're working on getting on
>> for
>> 6500 as well.
>> http://www.cisco.com/c/en/us/support/docs/routers/asr-9000-series-agg
>> regation-services-routers/116999-problem-line-card-00.html
>> On Tue, May 6, 2014 at 1:34 PM, <bedard.phil at gmail.com<mailto:bedard.phil at gmail.com>> wrote:
>>> I would like to see Cisco send something out...
>>> -----Original Message-----
>>> From: "Drew Weaver" <drew.weaver at thenap.com<mailto:drew.weaver at thenap.com>>
>>> Sent: ÿÿ5/ÿÿ6/ÿÿ2014 11:42 AM
>>> To: "'nanog at nanog.org<mailto:nanog at nanog.org>'" <nanog at nanog.org<mailto:nanog at nanog.org>>
>>> Subject: Getting pretty close to default IPv4 route maximum for
>>> 6500/7600routers.
>>> Hi all,
>>> I am wondering if maybe we should make some kind of concerted effort
>>> to remind folks about the IPv4 routing table inching closer and
>>> closer to the 512K route mark.
>>> We are at about 94/95% right now of 512K.
>>> For most of us, the 512K route mark is arbitrary but for a lot of
>>> folks who may still be running 6500/7600 or other routers which are
>>> by default configured to crash and burn after 512K routes; it may be
>>> a valuable public service.
>>> Even if you don't have this scenario in your network today; chances
>>> are you connect to someone who connects to someone who connects to
>>> someone
>>> (etc...) that does.
>>> In case anyone wants to check on a 6500, you can run:  show platform
>>> hardware capacity pfc and then look under L3 Forwarding Resources.
>>> Just something to think about before it becomes a story the
>>> community talks about for the next decade.
>>> -Drew

  Jon Lewis, MCP :)           |  I route
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