Transport issue (was: audio call Thursday: Minutes)

Krishna Kurpati kkrishna at IPCELL.COM
Thu Apr 8 20:05:43 EDT 1999

I think both TCP and UDP should be provided as options. Particularly with Trunking Gateways
TCP can be used as transport mechanism. Since there would be less number of these gateways (in most cases
two or four per Call Agent) there will be less number of connections to manage. TCP provides better communication with
Trunking gateways in that there is no need to maintain timers and retransmission acks for large number of transactions between
Call Agent and Trunking gateway. Three-way hand shaking and retransmission will be costly in this case.

For residential gateways they may be over 10000
per Call Agent. Managing 10000 connections is not a good idea. Also, only 5-10% of the time, residential gateway will communicate
with call agent. For this maintaining a connection is big overhead. In this case, UDP is preferred.

IMHO, there is a need to segragate transport profiles for residential gateways and trunking gateways.


Krishna Kurapati

-----Original Message-----
From:   Christian Huitema [SMTP:huitema at]
Sent:   Thursday, April 08, 1999 3:40 PM
To:     Greene, Nancy-M [CAR:5N10:EXCH]; 'megaco at'; 'itu-sg16 at'
Subject:        Transport issue (was: audio call Thursday: Minutes)

> 7) transport issues
> There was discussion on what to use for interoperability purposes until
> actual transport is agreed on. Some people wanted to mandate TCP for the
> others said UDP + the message acks, + the addition of timers would be
> better. Are there MG manufacturers that do not want to put TCP in their
> even if only for demonstration purposes? If there is opposition to TCP
> for demonstration purposes, then we would go with UDP + message acks, +
> timers. Chip Sharp reminded us that SGCP worked just fine with UPD,
> and timers.  ===> An issue for the mailing list.

Using TCP would be a serious problem in large configurations.  Our
experience is that UDP+timers has a wider applicability and is not in
practice harder to implement than TCP -- you have to manage timers, but
then you don't have to manage connections.

Christian Huitema
Please note my new address: huitema at

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