[c-nsp] Routing-induced latency

[christian.macnevin at uk.bnpparibas.com]

Hi all,

In a campus environment I'm working on, I'm consistently being asked to 
'reduce latency' between devices. So here's my question.
In (usually Catalyst) hardware, should you expect to see any latency 
induced by routing? By which I mean, if all routes are present
in the table, and you're running MLS CEF, I would expect that the 
switching is being done in hardware, and we should be introducing
zero latency. The older kit in here is not running CEF, so will be fast 
switching, I presume, which may sitll incur processor overhead.

Is that assumption correct? That in the absence of a converging network, 
there should in theory be no latency induced by switching
between two VLANs on the same switch as opposed to switching between two 
hosts on the same VLAN?

Cheers
Christian


This message and any attachments (the "message") is 
intended solely for the addressees and is confidential. 
If you receive this message in error, please delete it and
immediately notify the sender. Any use not in accord with
its purpose, any dissemination or disclosure, either whole
or partial, is prohibited except formal approval. The internet
can not guarantee the integrity of this message.
BNP PARIBAS (and its subsidiaries) shall (will) not
therefore be liable for the message if modified. 

**********************************************************************************************

BNP Paribas Private Bank London Branch is authorised
by CECEI & AMF and is regulated by the Financial Services
Authority for the conduct of its investment business in
the United Kingdom.

BNP Paribas Securities Services London Branch is authorised 
by CECEI & AMF and is regulated by the Financial Services 
Authority for the conduct of its investment business in 
the United Kingdom.
  
BNP Paribas Fund Services UK Limited is authorised and 
regulated by the Financial Services Authority