One question about VoIP system!!!! - 未名空间MITBBS历史存档

One question about VoIP system!!!!# EmergingNetworking - 热门网络技术

Q*e2006-03-09 08:03

1 楼

I have one question about VoIP phone.
In traditional analog phone, if two
or more phones are installed in one
room, somebody outside call it. Both
phones will ring at the same time,
and after one phone's handset is
picked up, the other phone stop ringing.
How does current VoIP system implement
the same function? Please give some
call flow example, that would be
helpful!
Thanks a lot!

z*r2006-03-09 08:03

2 楼

一样的。SIP对于所有registered的terminal都振铃。

【在 Q*******e 的大作中提到】

: I have one question about VoIP phone.
: In traditional analog phone, if two
: or more phones are installed in one
: room, somebody outside call it. Both
: phones will ring at the same time,
: and after one phone's handset is
: picked up, the other phone stop ringing.
: How does current VoIP system implement
: the same function? Please give some
: call flow example, that would be

Q*e2006-03-09 08:03

3 楼

Yeah, you got the point!
This is caled Look for Shared Call Appearance (SCA) and Bridged Line
Appearance (BLA). There are some internet drafts on IETF.
Also, the phones need to support RFC 3265
(SUBSCRIBE/NOTIFY) and RFC 4235 (Dialog event package) in addition
to basic SIP RFC.
The examples of the call flow can be found in draft-ietf-sipping-service-
examples-10.txt
Single Phone Extension describe how it works.
From the point, I think we should study hard!

z*r2006-03-09 08:03

4 楼

why would you think so?
just say what you want to say, make things straight, don't play games

l*y2006-03-09 08:03

5 楼

my two cents: for voip, sip registar should keep track of all endpoints that
register under one sip url. if the sip url gets an invite, the register can
route the invite to all endpoints, and as soon as one endpoints sends 200ok,
cancel the other invites. this is assuming the sip transaction is going
through the registar (there can be proxies/directors in between)
that's one way of doing it. i think MS LCS looks up the most recently-active
endpoint and only send invite to that endpoint, at least

【在 z**r 的大作中提到】

: why would you think so?
: just say what you want to say, make things straight, don't play games

c*a2006-03-09 08:03

6 楼

isn't this called FORK in SIP?

however

【在 l***y 的大作中提到】

: my two cents: for voip, sip registar should keep track of all endpoints that
: register under one sip url. if the sip url gets an invite, the register can
: route the invite to all endpoints, and as soon as one endpoints sends 200ok,
: cancel the other invites. this is assuming the sip transaction is going
: through the registar (there can be proxies/directors in between)
: that's one way of doing it. i think MS LCS looks up the most recently-active
: endpoint and only send invite to that endpoint, at least

Q*e2006-03-09 08:03

7 楼

That's too general!
Just some concept from usage,
not from implementation.

done

【在 z**r 的大作中提到】

: why would you think so?
: just say what you want to say, make things straight, don't play games

Q*e2006-03-09 08:03

8 楼

Yeah, you got the point!
This is caled Look for Shared Call Appearance (SCA) and Bridged Line
Appearance (BLA). There are some internet drafts on IETF.
Also, the phones need to support RFC 3265
(SUBSCRIBE/NOTIFY) and RFC 4235 (Dialog event package) in addition
to basic SIP RFC.
The examples of the call flow can be found in draft-ietf-sipping-service-
examples-10.txt
Single Phone Extension describe how it works.
From the point, I think we should study hard!

【在 c*a 的大作中提到】

: isn't this called FORK in SIP?
:
: however

z*r2006-03-09 08:03

9 楼

一样的。SIP对于所有registered的terminal都振铃。

【在 Q*******e 的大作中提到】

: I have one question about VoIP phone.
: In traditional analog phone, if two
: or more phones are installed in one
: room, somebody outside call it. Both
: phones will ring at the same time,
: and after one phone's handset is
: picked up, the other phone stop ringing.
: How does current VoIP system implement
: the same function? Please give some
: call flow example, that would be

c*a2006-03-09 08:03

10 楼

glad to see you are doing some serious reaading. type of discussions here on
bbs is suitable for more generic, high level, and nobody will take any
responsibility of being wrong.
But I do see many subscribers of certain mailing list take the quesions/
answers very seriously. they do not want ruin their reputation by giving wrong
answers:)

【在 Q*******e 的大作中提到】

: Yeah, you got the point!
: This is caled Look for Shared Call Appearance (SCA) and Bridged Line
: Appearance (BLA). There are some internet drafts on IETF.
: Also, the phones need to support RFC 3265
: (SUBSCRIBE/NOTIFY) and RFC 4235 (Dialog event package) in addition
: to basic SIP RFC.
: The examples of the call flow can be found in draft-ietf-sipping-service-
: examples-10.txt
: Single Phone Extension describe how it works.
: From the point, I think we should study hard!

c*a2006-03-09 08:03

11 楼

glad to see you are doing some serious reaading. type of discussions here on
bbs is suitable for more generic, high level, and nobody will take any
responsibility of being wrong.
But I do see many subscribers of certain mailing list take the quesions/
answers very seriously. they do not want ruin their reputation by giving wrong
answers:)

【在 Q*******e 的大作中提到】

: Yeah, you got the point!
: This is caled Look for Shared Call Appearance (SCA) and Bridged Line
: Appearance (BLA). There are some internet drafts on IETF.
: Also, the phones need to support RFC 3265
: (SUBSCRIBE/NOTIFY) and RFC 4235 (Dialog event package) in addition
: to basic SIP RFC.
: The examples of the call flow can be found in draft-ietf-sipping-service-
: examples-10.txt
: Single Phone Extension describe how it works.
: From the point, I think we should study hard!

z*r2006-03-09 08:03

12 楼

why would you think so?
just say what you want to say, make things straight, don't play games

【在 c*a 的大作中提到】

: glad to see you are doing some serious reaading. type of discussions here on
: bbs is suitable for more generic, high level, and nobody will take any
: responsibility of being wrong.
: But I do see many subscribers of certain mailing list take the quesions/
: answers very seriously. they do not want ruin their reputation by giving wrong
: answers:)