Subject: Re: LFB topology reconfguration

From: "Joel M. Halpern" <[email-masked]>
Date: Wed, 5 Nov 2003 22:59:28 -0500

It is my opinion that changing services on the fly is quite supportable and
useful.   No, I do not expect the change to be fequent.  But once a month
is more than often enough to need support.

And I would expect that many reconfigurable FEs would be able to cope with
changes on the fly.
A typical sequence of events might be:
1) Create / select a (new) set of LFBs for the new service.
2) Create a new output from a classifier, and connect it to the new service
path
3) Add filter entries to the classifier selecting traffic to get the new
service.

In fact, in many cases 1 and 2 would occur based on service definition, and
3 would occur based on sales / customer provisioning.

Basically, LFB topology modification is service provisioning.  It is
certainly not done at the same rate as customer provisioning.  But it is a
behavior that operators generally seek to have, and seek to have without
needing to disable service delivery components.  (In my experience "demand"
is more accurate than seek, but your mileage may vary.)

Yours,
Joel

At 06:41 PM 11/5/2003 -0800, you wrote:
>4) I imagine before you change service on FE from A to B, you probably
>have to stop sending packets to this FE all together if you don't want to
>have unpredictable behavior or loss of traffic temporarily. So it is
>almost equivalent to take down an FE and plug in a new one later, isn't it?

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From: Weiming Wang <[email-masked]>
Date: Thu, 6 Nov 2003 12:54:49 +0800

I'm thinking if we need to change the LFB topology so as to support RSVP to setup a 
connection and reserve resources for it? The same is for Diffserv.  If the answer is yes,
obviously the LFB topology will be changed frequently. 
 
Weiming

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From: "Joel M. Halpern" <[email-masked]>
Date: Thu, 6 Nov 2003 00:02:58 -0500

My guess is that
1) To assign a subset of customer traffic to an existing DiffServ service
will not require LFB reconfiguration on almost any FE.
2) To deploy a new DiffServ service to be used by customers will require
reconfiguration on many FEs.
3) To accept an RSVP request and assign resources to a flow in an RSVP
capable FE configuration will likely not require any LFB reconfiguration.
4) To enable RSVP support on an LFB that was not used for it (but has the
necessary capabilities) will require LFB reconfiguration on many FEs.

Yours,
Joel M. Halpern

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From: Alan DeKok <[email-masked]>
Date: Thu, 6 Nov 2003 10:32:51 -0500

> will not require LFB reconfiguration on almost any FE.
...

  I would tend to agree.

  For me, the boundary between internal changes to an LFB's
configuration, and changes to inter-LFB connections is most often a
protocol boundary.  Provisioning new connections/services within a
protocol requires updating entries in the LFB's which implement that
protocol.  Provisioning a new protocol requires re-arranging LFB's, or
creating new LFB's.

  Alan DeKok.