Phone numbers and dial strings Rohan Mahy & Brian Rosen rohan@cisco.com • brian.rosen@marconi.com

Phone Number vs. Dial String Global Number: tel:+140852685708 Local Number tel:5268570;phone-context=cisco.com Context Dial String 8p5268570

What we agree on Don’t mess with userparts of SIP URIs if they are not yours Some SIP domains have numeric usernames/userparts. Sometimes these conflict with phone numbers and dial strings. Some folks will need a user=phone parameter Phones and other UAs having a dial plan is good thing

We agree: continued User=phone parameter in SIP means that the userpart of a SIP URI is a valid RFC2806bis tel: URI tel: URI can be a global number, or a local number with phone-context: tel:1234;phone-context=example.com some devices are really stupid and need a proxy to translate dial strings for them. the proxy needs to know if it should do digit map translation when it gets a request

Where we disagree: How do you keep dial string contexts and local phone number contexts separate? Proposal 1: Use separate contexts. Each context handles either dial strings or local numbers. Proxies need to be configured to know which is which: tel:123;phone-context=acme.com vs. site.acme.com Proposal 2: New user=dialstring parameter. Userpart is an RFC 3601 dial string with a context userpart parameter. Can have pause and wait: sip:9,411;context=site.acme.com@provider.net ;user=dialstring