rangha at microsoft
Jun 26, 2012, 9:36 AM
Post #11 of 11
Agreed...Punting is specifically hardware related issue - applicable to the 3A, 3B, and 3BXL PFC/DFC daughter cards. Verify punts using - "sh tcam global acl in ipv6" command. Workaround is using "platform ipv6 acl fragment hardware" command and is specific to the 6500/7600. The command enables the ipv6 fragements to be forwarded in HW with some tradeoff to ACL activity. Per Cisco - this was corrected in the 3C daughtercard.
RE: discussion: Enabling IPv6 on Cisco 6500/7600 breaks IPv4 Internet connectivity
[In reply to]
From: Mikael Abrahamsson [mailto:swmike [at] swm]
Sent: Monday, June 25, 2012 10:36 PM
To: Ranganath Hande
Cc: ipv6-ops [at] lists
Subject: Re: discussion: Enabling IPv6 on Cisco 6500/7600 breaks IPv4 Internet connectivity
On Mon, 25 Jun 2012, Ranganath Hande wrote:
> It is fairly common for RP utilization to go up initially when either
> v4 or v6 internet BGP peer comes up first time--due to large number of
> BGP prefixes that router has to process. In case of v6, impact is more
> visible as resource utilization is 4 times higher. Possible solutions
> are --
In case of PFC3B(-XL), this is also of interest once IPv6 traffic is
PFC3B will by default punt IPv6 packets with fragmentation header to RP and route them there, with the obvious performance penalty this incurs.
Workaround is to change this behaviour, meaning ACLs won't work for packets with fragmentation header anymore:
#platform ipv6 acl fragment hardware ?
drop Drop IPv6 fragments at hardware
forward Forward IPv6 fragments at hardware
PFC3C is supposed to not be affected.
Mikael Abrahamsson email: swmike [at] swm