Takei,

I don't believe that anybody has reached a consensus on what this means. Some say that this field represents the telephone number prefixes, while others believe it means something else. It was originally proposed as a means to access a device that supports a particular technology, as I understand it. For example, on the VoIP network, one might dial "7" first in order to access a GW that supports fax. The assignment of such "prefixes" is certainly not subject to standardization. Some equipment will automatically insert this prefix value and other equipment will not. Likewise, some GWs know to strip such prefixes, while others cannot.

Because of this ambiguity, vendors have implemented various things. For interoperability purposes, I would strongly advise that you not expect a GK to understand this field. If you want to use this field, I would suggest that you align the usage of this field with Gatekeepers that you wish to interoperate with.

H.323v4 should address this and other related issues.

Paul

----- Original Message ----- From: < $BIp0f (J $B9nL@ (J takei744@AINET.OKI.CO.JP)> To: ITU-SG16@mailbag.cps.intel.com Sent: Tuesday, April 04, 2000 9:47 AM Subject: SupportedProtocol & SupportedPrefix in RAS

Hi all,

I am currently implementing a gatekeeper that supported only E.164

alias.

H.323-ID is not supported in the current version. So I have a question. I don't enough understand the meaning of SupportedProtocol included the

GatewayInfo in the

EndpointType InformationElement. And the meaning of supportedPrefixes included VoiceCaps, T120OnlyCaps,

H323Caps and so on.

Please let me know, if anybody understand it.

Regards, Katsuaki Takei

$$$ Katsuaki Takei OKI Electric Industry Co., Ltd. 10-16, Shibaura 4-Chome, Minato-ku, Tokyo 108-0023, Japan Tel: +81-3-3454-2111 (EXT:46413) FAX: +81-3-3798-7684 E-mail: takei744@oki.co.jp $$$