[c-nsp] ASR-100x intro

[Mack McBride]

One of the questions I haven't gotten a good answer to.
The ESP actually has the hardware for the route table.
The ESP20 and ESP40 handle 4 million routes.
The others handle less (the 5G for examples handles 500k v4 or 125k v6).
What happens to the other routes?
It seems they could get handled in software but the ESP is basically software anyway.
So the situation is clearly opaque.

The MX80 from juniper for example has the same situation and is equally opaque.

LR Mack McBride
Network Architect

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Nick Hilliard
Sent: Thursday, February 07, 2013 8:45 AM
To: Adam Vitkovsky
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] ASR-100x intro

On 07/02/2013 12:04, Adam Vitkovsky wrote:
> Wow so from ASR1004 and upwards we're indeed not limited by the number 
> of VPN routes anymore so goodbye RR Planes (I'm going to miss this 
> state of art BGP design). 8k sessions is also enough to serve a 
> particular region

on the asr1k, you can stop propagation of the best path rib entries to the hardware fib, which will usually max out at either 500k or else 1m entries.
 This means that when acting as a RR, the asr1k is constrained only by the amount of RAM and the CPU power.  The FIB size is no longer relevant.

The command to do this is:

router bgp 64512
 table-map rm-filter-bgp-to-fib		<------- magic sauce
 neighbor x.y.z.w route-reflector-client  [etc]

route-map rm-filter-bgp-to-fib permit
 match blahblahblah

You can then tune the rm-filter-bgp-to-fib route-map only to permit what you want in your TCAM instead of getting everything, including VPN prefixes.

So on an asr1001, which you can pimp up to 16G, you could handle many full DFZ VPNs separately, even though the box can only handle 1m prefixes in hardware.  Just be careful about the ASR1002: the base model can only take 4G RAM and this is not upgradable.  This limitation is fixed in the ASR1002X.

Nick


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