nanog mailing list archives
Re: subnet prefix length > 64 breaks IPv6?
From: sthaug () nethelp no
Date: Wed, 28 Dec 2011 15:41:14 +0100 (CET)
Most vendors have a TCAM that by default does IPv6 routing for netmasks <=64. They have a separate TCAM (which is usually limited in size) that does routing for masks >64 and <=128.
Please provide references. I haven't seen any documentation of such an architecture myself.
TCAMs are expensive and increase the BOM cost of routers. Storing routes with masks > 64 takes up twice the number of TCAM entries as the routes with masks <= 64. Since IPv6 is *supposed* to work with /64 masks, most vendors (usually the not-so-expensive-routers) provide a smaller TCAM for > /64 masks.
Ah, but do the "not-so-expensive-routers" use TCAM at all? Steinar Haug, Nethelp consulting, sthaug () nethelp no
Current thread:
- Re: subnet prefix length > 64 breaks IPv6?, (continued)
- Re: subnet prefix length > 64 breaks IPv6? Joel Maslak (Dec 27)
- Re: subnet prefix length > 64 breaks IPv6? Chuck Anderson (Dec 27)
- Re: subnet prefix length > 64 breaks IPv6? Ray Soucy (Dec 24)
- Re: subnet prefix length > 64 breaks IPv6? Glen Kent (Dec 25)
- Re: subnet prefix length > 64 breaks IPv6? sthaug (Dec 25)
- Re: subnet prefix length > 64 breaks IPv6? Iljitsch van Beijnum (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Ray Soucy (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Alexandru Petrescu (Dec 29)
- Re: subnet prefix length > 64 breaks IPv6? sthaug (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Glen Kent (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? sthaug (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Ryan Malayter (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? sthaug (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Ray Soucy (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? sthaug (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Alexandru Petrescu (Dec 29)
- Re: subnet prefix length > 64 breaks IPv6? Ray Soucy (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Leo Bicknell (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Glen Kent (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Jeff Wheeler (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Ray Soucy (Dec 28)
- Re: subnet prefix length > 64 breaks IPv6? Jeff Wheeler (Dec 28)