[c-nsp] Feature request

[christopher.a.kane at jpmchase.com]

Since dependency upon network availability, IRT revenue, never 
decreases....it seems more and more often people like to schedule complete 
downtime maintenance windows to perform seemingly benign tasks. We often 
have folks requesting we route traffic away from a device that we intend 
to perform maintenance on even if it's as simple as plugging in a new, 
non-production T1 or changing the speed/duplex settings on a port that 
resides on a different module and has nothing to do with their production 
route. Erring this much on the side of caution seems like a sledgehammer 
approach. I'd much rather be able to reassure folks that certain tasks can 
be performed without impact to traffic flow. But over the years...too many 
bugs or mishaps such as configuration errors or a field engineer sneezing 
on a router causes said router to reload. You want a true example? How 
about inserting a flash card into a box that shot CPU utilization up to 
>95% and caused packet loss.

I have a feature request and was hoping Rodney or one of the other Cisco 
employed lurkers could point me in the right direction. My request is for 
a 'Detour' feature. What I'm looking for is the ability to route any new 
traffic flows in a different direction and allow existing traffic flows to 
bleed off. Once all the traffic has detoured to my alternate connection, I 
could perform maintenance and then remove the detour and allow the traffic 
to return to the primary path. The catch is that I don't want this to be 
disruptive. The programming language would read something like: for all 
existing flows across interface A/B, permit them to continue. But for any 
new data flows, detour them to interface X/Y. It seems that we could use 
data like Netflow and we'd probably have to alter CEF entries to make it 
happen. Maybe even allow the feature to be shared with a peering router so 
that we could not only alter the path through various interfaces on one 
router but ship them to the peering detour router such as would be 
available in an HSRP/VRRP configuration. As far as I know, up to now, all 
intentions to route traffic across other available paths is disruptive to 
existing source/destination flows. I'm not aware of a feature that gently 
moves traffic another direction without causing some interruption to 
existing flows. A feature like a detour could be leveraged to stage a 
device to be ready for maintenance. If we could configure the router to 
start detouring traffic to an alternate route at a particular time (either 
immediately or in a set future day/minute/second) we could gently direct 
traffic away from our maintenance domain without customers having to be 
engaged and prepared to possibly reset applications because their TCP 
sessions were hung by the change in flow.

Make sense?

-chris

Chris Kane
CCIE #14430
Network Engineering - Business Partner connectivity
JPMorgan Chase
w (614) 213-2923
c (614) 329-1906

-----------------------------------------
This transmission may contain information that is privileged,
confidential, legally privileged, and/or exempt from disclosure
under applicable law.  If you are not the intended recipient, you
are hereby notified that any disclosure, copying, distribution, or
use of the information contained herein (including any reliance
thereon) is STRICTLY PROHIBITED.  Although this transmission and
any attachments are believed to be free of any virus or other
defect that might affect any computer system into which it is
received and opened, it is the responsibility of the recipient to
ensure that it is virus free and no responsibility is accepted by
JPMorgan Chase & Co., its subsidiaries and affiliates, as
applicable, for any loss or damage arising in any way from its use.
If you received this transmission in error, please immediately
contact the sender and destroy the material in its entirety,
whether in electronic or hard copy format. Thank you.