nanog mailing list archives
Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header
From: Christopher Morrow <morrowc.lists () gmail com>
Date: Fri, 30 Sep 2011 01:55:55 -0400
On Fri, Sep 30, 2011 at 1:07 AM, Mikael Abrahamsson <swmike () swm pp se> wrote:
Just thought I'd share some operational info. PFC3B will by default punt IPv6 packets with fragmentation header to RP and route them there, with the obvious performance penalty this incurs.
when will vendors learn that punting to the RE/RP/smarts for packets in the fastpath is ... not just 'unwise' but wholesale stupid? :(
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
your recommendation is to ... forward? (or perhaps not 'recommendation' but: "Forward means do not pass go, just ship out the proper egress interface. drop means ... send to hell" If you do nothing the default behavior is to send the packet to the RP... why? (why would you want this packet sent to the RP? it's got a valid destination, no? so deliver it out the egress interface?) thanks! -chris
PFC3C is supposed to not be affected. A lot of Teredo and 6to4 traffic has fragmentation headers, so this actually is a real problem. We discovered this at our Teredo relay upstream router. -- Mikael Abrahamsson email: swmike () swm pp se
Current thread:
- Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Mikael Abrahamsson (Sep 29)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Christopher Morrow (Sep 29)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Mikael Abrahamsson (Sep 29)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Saku Ytti (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Christopher Morrow (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Saku Ytti (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Christopher Morrow (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Saku Ytti (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Nick Hilliard (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Mohacsi Janos (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Nick Hilliard (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Christopher Morrow (Sep 30)
- Re: Cisco 7600 PFC3B(XL) and IPv6 packets with fragmentation header Christopher Morrow (Sep 29)