[c-nsp] Pre-create virtual interfaces

[Oliver Boehmer (oboehmer)]

Robert E.Seastrom <mailto:rs at seastrom.com> wrote on Tuesday, May 17,
2005 4:24 PM:

> "Oliver Boehmer (oboehmer)" <oboehmer at cisco.com> writes:
> 
>> ack, but in 12.3 code, you rather want to use virtual-access
>> subinterfaces (if possible), making this command redundant. VAI
>> subinterfaces are more performant than full VAI..
> 
> can you elaborate?  under what circumstances can i get better
> throughput?  if i could squeeze a little more life out of the
> 7206VXR/NPE300 combination as an LNS, that would be spiffy.

Please note that virtual-access subinterface speed up the control plane
(i.e. cause less CPU cycles when a call comes up or goes down), it does
not affect packet/sec through the interface. So if your CPU is mostly
busy switching packets, VAI subinterfaces won't help too much.

> i already pre-clone more than enough interfaces considering how many
> customers i have pile on to the box.
> 
> a cursory search found this:
> 
>
http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_
guide09186a00800f4b47.html
> 
> i'm running 12.3T; did i get this by default and not realize it?

Yes. If you're running 12.3T and still see users terminated on "real"
virtual-access (i.e. Vi2, Vi3, Vi4, etc..), you're probably using a
feature which is not supported on VAI sub-ifs. Use the "test
virtual-template <n> subinterface" to identify the feature and evaluate
removing/replacing it..

	oli