[c-nsp] unnumbered SVI on 6500/sup720

[Phil Mayers]

On 27/04/11 11:44, Phil Mayers wrote:

> I've been unable to get this working on sup720/12.2(33)SXI5. I get:
>
> IP ARP req filtered src 155.198.60.2 0011.0a3a.a9c7, dst 155.198.60.1
> 0000.0000.0000 wrong cable, interface Vlan600
>

Ah, never mind - it appears that you either need to:

  a. use DHCP, in which case the sup installs a /32 static route. Does 
anyone have details of how the CPU does this? I see there's a "sh ip 
route dhcp" command, which shows:

S    155.198.60.248/32 is directly connected, Vlan600
           DHCP Server: 155.198.63.11   Lease expires at Apr 27 2011 ..

...which implies the sup will expire the route at some future point? 
What if the router reloads in the meantime? Presumably all clients fall 
off-net until they renew their DHCP leases?



  b. insert the static route yourself, with:

ip route 155.198.60.248 255.255.255.255 Vlan600

...but if you're using VRFs/MPLS VPNs as we are, the sup complains:

% For VPN routes, must specify a next hop IP address if not a 
point-to-point interface

...so you need to give a null next-hop:

ip route vrf PROD 155.198.60.248 255.255.255.255 vl600 0.0.0.0

Worryingly this is NVGENed as:

ip route vrf PROD 155.198.60.248 255.255.255.255 vl600

...which makes we wonder if it'll parse it on a reload, given that it 
won't at the CLI.



I'll be honest; this looks a little bit more brittle than I'd like.