[c-nsp] Cisco 6500/Sup32 Sub-interface MTU Issue

[Gert Doering]

Hi,

On Sun, Mar 18, 2012 at 01:15:34PM +0000, Markus Binder wrote:
> I am wondering which Linecard on the Sup32 (or Sup720) Platform supports user settable MTUs on Routed Sub-interfaces?

"Yes".  Sort of  :-)

> We want to use one physical Port for MPLS Backbone Uplink and IP Downlink to a customer at the same time.
> As MPLS Backbone Link we have a VLAN configured with a MTU of 9216 Bytes, as IP Downlink we want to use the "normal" 1500 Byte MTU each on separate Routed Sub-Interfaces.

This works fine for IP-Subinterfaces, by using "ip mtu 1500"...

> The Routed Sub-interfaces are required for the support of Xconnect MPLS connectivity of the IP Downlink Port as Sup32 does not support Xconnect on SVIs without WAN Cards.

... but *this* doesn't work with a settable MTU, and this sucks big time,
because it means that you have to have 9216 on both ends.

(Maybe this got added in the last year or so, but last time I ran into
this issue, it wasn't possible)

> Any other ideas of how to achieve that?

Curse, spit, split the link into "big-mtu" and "small-mtu" VLANs.

gert

-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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