Internet Edge Router replacement - IPv6 route table size considerations

Bill Blackford bblackford at
Wed Mar 9 07:53:01 CST 2011


With address exhaustion and deaggregation, the table is only going to
get bigger so choosing anything now that can only handle anything
south of 1M routes is not a wise investment.

Several posters have recommended ASR1002 and MX80. I use both of these
platforms in my environment and have been quite pleased with both.

ARA100x. Cisco has lower/cheaper options here including a 1RU device.
I don't have the specs handy, but these are lacking in scalability
that you will most likely need. I believe the forwarding cap is 2.5G.
With the ASR1002, you can start up with the 5G forwarding board.

The MX80. There are several models/bundles. A good choice for you may
be the MX80-5G. Incidentally, the "5G" does not mean 5gig. It ships
with a 20 port ge MIC that will do line rate. The other MIC and the
on-board 4X 10GE are disabled. As previously mentioned, it doesn't use
TCAM so your V4, V6 routes don't share finite resources with each
other or MAC entires, etc. If you're familiar with the benefits if
JUNOS - once you've used it for awhile - it's hard to go back.

If your environment is rapidly growing, stay away from low CAM
limits,anything that's runs in software, (C7200, C7330, J6350), and
make the jump to line-rate hardware devices.


On Tue, Mar 8, 2011 at 4:15 PM, Chris Enger <chrise at> wrote:
> Greetings,
>    I am researching possible replacements for our Internet edge routers, and wanted to see what people could recommend for a smaller chassis or fixed router that can handle current IPv4 routes and transition into IPv6.  Currently we have Brocade NetIron 4802s pulling full IPv4 routes plus a default route.  I've looked at Extreme, Brocade, Cisco, and a few others.  Most range from 256k - 500k IPv4 and 4k - 16k IPv6 routes when CAM space is allocated for both.  The only exception I've found so far is the Cisco ASR 1002, which can do 125k v6 along with 500k v4 routes at once.  I'm curious if any other vendors have comparable products.
> My concern is trying to find a router (within our budget) that has room for growth in the IPv6 routing space.  When compared to the live table sizes that the CIDR report and routeviews show, some can't handle current routing tables, let alone years of growth.  BGP tweaks may keep us going but I can't see how 16k or fewer IPv6 routes on a router is going to be viable a few years from now.
> Thank you,
> Chris Enger

Bill Blackford
Network Engineer

Logged into reality and abusing my sudo privileges.....

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