Subject: [IPTEL] Re: draft-ietf-iptel-trip-gw-00.txt has been posted

From: Sarabjeet Chugh <[email-masked]>
Date: Sun, 23 Jun 2002 18:19:45 -0700

Hi Dhaval, et. al.

I have some questions/concerns.

1) Aside from the three functions of the TRIP-Lite gateway that were 
listed, viz.
- The initial OPEN phase, exchange of keepalive timers, and the process of 
bringing up the state machine.
- Sending of one or more UPDATE messages containing the routes and 
parameters of the gateways.
- Sending of a periodic keepalive.
Won't the TRIP-GW gateways also need to keep track of which LS/Proxy to 
send its updates to ? That is, in scenarios when LS/Proxy are deployed in a 
redundancy or HA mode, shouldn't a mechanism be implemented within the 
TRIP-GW gateways to detect the change from Primary LS to backup/secondary 
LS and vice versa?

As an extension to this thought, in cases when LSs are deployed in a 
load-sharing manner for a given POP, as shown in figure below:

         POP1
----------------------------------------------
|                 GW1           |
|                 /                     |
|                /                      |
|           LS2/-------GW2              |
|          /                    |
|           /     GW3           |
|          /      /             |
|   LS1/------LS3/---- GW4      |
|      \                                |
|       \                               |
|       LS4-----GW5             |
|        \                      |
|          \                    |
|           GW6                 |
|---------------------------------------------

What should be the best mechanism by which LS2 (that receives updates from 
GW1 and GW2), LS3 (that receives updates from GW3 and GW4) and LS4 (that 
receives updates from GW5 and GW6) respectively send their consolidated 
update to the IP-facing Location Server , LS1? In this case LS1 should do 
the ultimate consolidation for a given route/destination through this PoP.
In this scenario, how would the functionality of the attribute 
"TotalCircuitCapacity" have to be modified?

2) TotalCircuitCapacity attribute
For a given PoP, the total number of routes to a destination DNIS/group of 
DNIS/prefix may be fixed because of a pre-defined administrative policy 
between the provider and the customers. In that case, on what basis will 
individual gateways be able to assign values to the TotalCircuitCapacity 
attribute for a given destination prefix or DNIS group?
The consolidated information is only available at LS, where the total 
available circuits for a given destination are aggregated (as per Section 
4.2.4).
So, shouldn't there be sync mechanism from LS to TRIP-GW gateways by which 
the global TotalCircuitCapacity for a given destination for the entire PoP 
be in sync with the sum of local values of TotalCircuitCapacity attributes 
for the same destination present in all gateways? This can allow 
implementation of circuit assignment based on pre-agreed upon policies 
between the provider and retailer.

Regards,
Sarabjeet S. Chugh
VGDBU Software Engineer
Cisco Systems, Inc.
Email: [email-masked]
Phone: (408) 853-5504

 >Hi Folx, The draft is now available on the ftp server: 
ftp://ftp-eng.cisco.com/dhaval/draft-ietf-iptel-trip-gw-00.txt
 >If someone has problems retrieving it, please email directly and we will 
email a copy to you.
 >Please let us know if you have any questions.
 >Thx, Dhaval (for the trip-gw team)

---

From: Dhaval Shah <[email-masked]>
Date: Sun, 23 Jun 2002 21:47:52 -0700

Hi Sarabjeet,

At 06:19 PM 6/23/2002 -0700, Sarabjeet Chugh wrote:
>send its updates to ? That is, in scenarios when LS/Proxy are deployed in 
>a redundancy or HA mode, shouldn't a mechanism be implemented within the 

A Trip-lite gateway can have associations with multiple LS's. So one 
possible scenario, in case the fail-over is'nt transparent, is for the 
Trip-lite gateway to have assocation with both the primary and secondary LS's.

>load-sharing manner for a given POP, as shown in figure below:

Not sure if I understand your question correctly, but I guess you could add 
the TotalCircuitCapacity.

>attribute for a given destination prefix or DNIS group?

If I understand your question correctly, this is a local policy issue.

>between the provider and retailer.

TRIP-GW gateways feed information into the LS and then LS has the 
configured policies and also does the assignment so it can locally choose 
to do whatever it wants with that information. I may be missing something 
but I guess what you mention in your last sentence can be 
achieved,  without the need for the sync from LS to gateways..

Thx for your input,
Dhaval