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matt at venturevoip.com
Guest

Posted: Sun Mar 09, 2008 10:05 pm Post subject: [asterisk-users] Microsoft Office Communications Server

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Has anyone done any integration with this? All I know so far is that it appears to use some non standard form of SIP. Any pointers? - -- Kind Regards, Matt Riddell Director _______________________________________________ http://www.venturevoip.com (Great new VoIP end to end solution) http://www.venturevoip.com/news.php (Daily Asterisk News - html) http://www.venturevoip.com/newrssfeed.php (Daily Asterisk News - rss) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFH1KVoDQNt8rg0Kp4RAgSfAJ0aXGIkKi6kGAjZK8TtSV2mMj79qQCdHhAS 1jZ9sjtsTJ3O1R9J3giztw8= =Mlnt -----END PGP SIGNATURE-----

dbc_asterisk at advan.ca
Guest

Posted: Mon Mar 10, 2008 7:05 am Post subject: [asterisk-users] Microsoft Office Communications Server

Quote:

Has anyone done any integration with this?

All I know so far is that it appears to use some non standard form of
SIP.

Any pointers?

<sarcasm>
What!? Microsoft implementing something not compliant with official
standards. Your kidding?
</sarcasm>

Sorry Matt, no advice here but I just couldn't resist.
--
David Cook

lathama at lathama.com
Guest

Posted: Mon Mar 10, 2008 9:13 am Post subject: [asterisk-users] Microsoft Office Communications Server

They very likely purchased or licensed an engine from someone. Use
Wireshark and compare it to other SIP proxies/servers/gateways.
On Sun, Mar 9, 2008 at 11:05 PM, Matt Riddell <matt at venturevoip.com> wrote:

Quote:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Has anyone done any integration with this?

All I know so far is that it appears to use some non standard form of SIP.

Any pointers?

- --
Kind Regards,

Matt Riddell
Director
_______________________________________________

http://www.venturevoip.com (Great new VoIP end to end solution)
http://www.venturevoip.com/news.php (Daily Asterisk News - html)
http://www.venturevoip.com/newrssfeed.php (Daily Asterisk News - rss)
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.7 (MingW32)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFH1KVoDQNt8rg0Kp4RAgSfAJ0aXGIkKi6kGAjZK8TtSV2mMj79qQCdHhAS
1jZ9sjtsTJ3O1R9J3giztw8=
=Mlnt
-----END PGP SIGNATURE-----

_______________________________________________
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--
/*
Andrew Latham
LATHAMA (lay-th-ham-eh)
lathama at lathama.com
lathama at gmail.com

TuxTone Inc.
http://www.TuxTone.com
*/

kristian.kielhofner at...
Guest

Posted: Mon Mar 10, 2008 5:18 pm Post subject: [asterisk-users] Microsoft Office Communications Server

On Sun, Mar 9, 2008 at 11:05 PM, Matt Riddell <matt at venturevoip.com> wrote:

Quote:

Matt,

I believe OCS only supports SIP over TCP. You'll either need to use
Asterisk 1.6/trunk with SIP TCP or install SER/OpenSER as a UDP-TCP
proxy.

--
Kristian Kielhofner

mgraves at mstvp.com
Guest

Posted: Mon Mar 10, 2008 5:38 pm Post subject: [asterisk-users] Microsoft Office Communications Server

What is the logic of them using SIP over TCP? Is this a broad industry
trend? Or just the latest attempt to get around SIP/NAT issues?

Michael Graves
mgraves <at> mstvp.com
o(713) 861-4005
c(713) 201-1262
sip:mjgraves at pixelpower.onsip.com
skype mjgraves
FWD 54245

Quote:

-------- Original Message --------
Subject: Re: [asterisk-users] Microsoft Office Communications Server
From: "Kristian Kielhofner" <kristian.kielhofner at gmail.com>
Date: Mon, March 10, 2008 5:18 pm
To: "Asterisk Users Mailing List - Non-Commercial Discussion"
<asterisk-users at lists.digium.com>
On Sun, Mar 9, 2008 at 11:05 PM, Matt Riddell <matt at venturevoip.com> wrote:

Quote:

Matt,
I believe OCS only supports SIP over TCP. You'll either need to use
Asterisk 1.6/trunk with SIP TCP or install SER/OpenSER as a UDP-TCP
proxy.
--
Kristian Kielhofner
_______________________________________________
-- Bandwidth and Colocation Provided by http://www.api-digital.com --
asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
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shadowym at hotmail.com
Guest

Posted: Mon Mar 10, 2008 6:02 pm Post subject: [asterisk-users] Microsoft Office Communications Server

I would rather stick needles in my eyes but that's just me. -----Original Message----- From: Matt Riddell [mailto:matt at venturevoip.com] Sent: Sunday, March 09, 2008 8:05 PM To: Asterisk Users Mailing List - Non-Commercial Discussion Subject: [asterisk-users] Microsoft Office Communications Server -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Has anyone done any integration with this? All I know so far is that it appears to use some non standard form of SIP. Any pointers? - -- Kind Regards, Matt Riddell Director _______________________________________________ http://www.venturevoip.com (Great new VoIP end to end solution) http://www.venturevoip.com/news.php (Daily Asterisk News - html) http://www.venturevoip.com/newrssfeed.php (Daily Asterisk News - rss) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFH1KVoDQNt8rg0Kp4RAgSfAJ0aXGIkKi6kGAjZK8TtSV2mMj79qQCdHhAS 1jZ9sjtsTJ3O1R9J3giztw8= =Mlnt -----END PGP SIGNATURE-----

michiel at vanbaak.info
Guest

Posted: Mon Mar 10, 2008 6:16 pm Post subject: [asterisk-users] Microsoft Office Communications Server

On 15:38, Mon 10 Mar 08, mgraves at mstvp.com wrote:

Quote:

What is the logic of them using SIP over TCP? Is this a broad industry
trend? Or just the latest attempt to get around SIP/NAT issues?

Their setup implements some 'non standard extensions' on the
SIP standard and I think it was easier to do it in TCP.
(probably because they bought it from someone else, and that
someone did it it TCP)

Of course, because I'm not a MS developer that's only
guessing.

Quote:

Michael Graves
mgraves <at> mstvp.com
o(713) 861-4005
c(713) 201-1262
sip:mjgraves at pixelpower.onsip.com
skype mjgraves
FWD 54245

Quote:

_______________________________________________
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asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
http://lists.digium.com/mailman/listinfo/asterisk-users

--

Michiel van Baak
michiel at vanbaak.eu
http://michiel.vanbaak.eu
GnuPG key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x71C946BD

"Why is it drug addicts and computer aficionados are both called users?"

kristian.kielhofner at...
Guest

Posted: Mon Mar 10, 2008 6:27 pm Post subject: [asterisk-users] Microsoft Office Communications Server

On Mon, Mar 10, 2008 at 6:38 PM, <mgraves at mstvp.com> wrote:

Quote:

I would imagine it's because they plan on doing all kinds of "neat"
stuff with SIP including video, TXT, Windows Updates, who knows...
SIP over UDP has some pretty serious packet fragmentation issues. If
you end up with a large enough SDP or something that causes a SIP
packet to grow larger than the smallest MTU in the path between your
two endpoints it doesn't work (no fragmentation support with SIP over
UDP). SIP over TCP does not have this problem.

Also, you need SIP TCP support for TLS...

--
Kristian Kielhofner

klitzing at pool.infor...
Guest

Posted: Mon Mar 10, 2008 8:29 pm Post subject: [asterisk-users] Microsoft Office Communications Server

Hi!

Quote:

What is the logic of them using SIP over TCP? Is this a broad industry
trend? Or just the latest attempt to get around SIP/NAT issues?

I remember a quote of Henning Schulzrinne where he states that having
designed SIP with UDP in mind was the biggest mistake he (and Mark
Handle?) were to be found guilty of. I am not sure if this is what's
driving Microsoft's decisions, my guess is that this is/was mostly driven
by security reasons (and the new focus of Microsoft on security aspects).

Cheers, Philipp
* Taken from http://www.faqs.org/rfcs/rfc4168.html:

3.1. Advantages over UDP

All the advantages that SCTP has over UDP regarding SIP transport are
also shared by TCP. Below, there is a list of the general advantages
that a connection-oriented transport protocol such as TCP or SCTP has
over a connection-less transport protocol such as UDP.

Fast Retransmit: SCTP can quickly determine the loss of a packet,
because of its usage of SACK and a mechanism that sends SACK
messages faster than normal when losses are detected. The result
is that losses of SIP messages can be detected much faster than
when SIP is run over UDP (detection will take at least 500 ms, if
not more). Note that TCP SACK exists as well, and TCP also has a
fast retransmit option. Over an existing connection, this results
in faster call setup times under conditions of packet loss, which
is very desirable. This is probably the most significant
advantage of SCTP for SIP transport.

Congestion Control: SCTP maintains congestion control over the entire
association. For SIP, this means that the aggregate rate of
messages between two entities can be controlled. When SIP is run
over TCP, the same advantages are afforded. However, when run
over UDP, SIP provides less effective congestion control. This is
because congestion state (measured in terms of the UDP retransmit
interval) is computed on a transaction-by-transaction basis,
rather than across all transactions. Thus, congestion control
performance is similar to opening N parallel TCP connections, as
opposed to sending N messages over one TCP connection.

Transport-Layer Fragmentation: SCTP and TCP provide transport-layer
fragmentation. If a SIP message is larger than the MTU size, it
is fragmented at the transport layer. When UDP is used,
fragmentation occurs at the IP layer. IP fragmentation increases
the likelihood of having packet losses and makes NAT and firewall
traversal difficult, if not impossible. This feature will become
important if the size of SIP messages grows dramatically.

* Quote from http://tools.ietf.org/html/draft-jennings-sip-dtls-01:

There has been considerable discussion of why SIP needs DTLS when we
have TLS. This is the wrong question. The right question is why SIP
has UDP and TCP (not to mention SCTP). There are two reasons for
believing that UDP is likely to be an important protocol in SIP for
the foreseeable future.

o In theory, there is no problem building systems that terminate a
million TCP connections on a single host. In practice, the common
operating systems used for building SIP aggregation devices make
this impossible. To date, no one has demonstrated terminating
over 100k SIP TCP connections to a single host. Doing that many
connections with UDP has not been difficult.

o If we want to talk about "running code" for SIP, it's UDP. Unless
UDP is deprecated for SIP, it is important to provide a reasonable
level of security for it.

senad at bicom.us
Guest

Posted: Mon Mar 10, 2008 8:49 pm Post subject: [asterisk-users] Microsoft Office Communications Server

Kristian Kielhofner wrote:

Quote:

On Mon, Mar 10, 2008 at 6:38 PM, <mgraves at mstvp.com> wrote:

Quote:

Well...

I have been a MS windows desktop user for a while as many other people
have. It mostly works except at times one needs to maintain/repair what
one bought. I have switched Smile

Imagine, repairing an engine of your brand new car you just bought?
Imagine "restarting" your TV because it just froze? What if your shoes
have "just" changed colour to "blue screen"?
It will just not "pass", will it? ... You will DEMAND a service for your
car/TV,shoes or you may return it or whatever.

So.. Imagine how much your business will be affected with a phone SYSTEM
based on a such operating system, one which can not even meet basic
desktop user requirements let alone crucial every day in/out business
communications tool like a phone system.

At the end, if you do not answer a call some else will!!!
Senad Jordanovic
www.bicomsystems.com

senad at bicom.us
Guest

Posted: Tue Mar 11, 2008 8:04 am Post subject: [asterisk-users] Microsoft Office Communications Server

Razza wrote:

Quote:

I would suggest to you learning how to use text emails and quoting first
then you may have some responses that may be your worth while.
Senad

tzafrir.cohen at xorco...
Guest

Posted: Tue Mar 11, 2008 8:32 am Post subject: [asterisk-users] Microsoft Office Communications Server

On Tue, Mar 11, 2008 at 01:49:23AM +0000, Senad Jordanovic wrote:

Quote:

I have been a MS windows desktop user for a while as many other people
have. It mostly works except at times one needs to maintain/repair what
one bought. I have switched Smile

Imagine, repairing an engine of your brand new car you just bought?
Imagine "restarting" your TV because it just froze? What if your shoes
have "just" changed colour to "blue screen"?

TV sets and such are simple enough. But when the device gets more
sofficticated then, yes: reboot tends to become a first reaction.
routers and similar devices (even linux-based ones) don't provide you
much debugging help. And are known to crash occasionally.

Quote:

It will just not "pass", will it? ... You will DEMAND a service for your
car/TV,shoes or you may return it or whatever.

With such devices the software is often too buggy because there was not
enough time to develop and debug it.

Quote:

So.. Imagine how much your business will be affected with a phone SYSTEM
based on a such operating system, one which can not even meet basic
desktop user requirements let alone crucial every day in/out business
communications tool like a phone system.

Right. Asterisk never crashes. Asterisk is completely solid.

Quote:

At the end, if you do not answer a call some else will!!!

Three are not convincing enough. I think the following is more
convincing:

SIP/TCP will eat your babies!!!!!

--
Tzafrir Cohen
icq#16849755 jabber:tzafrir.cohen at xorcom.com
+972-50-7952406 mailto:tzafrir.cohen at xorcom.com
http://www.xorcom.com iax:guest at local.xorcom.com/tzafrir

rj2807 at gmail.com
Guest

Posted: Tue Mar 11, 2008 9:07 am Post subject: [asterisk-users] Microsoft Office Communications Server

I'd concur that allowing SIP to be transported over UDP was one of the
biggest mistakes made in the initial protocol design. In addition to
the issues stated below (such as IP fragmentation and how that impacts
NAT traversal), there are other unsolvable problems w/ SIP/UDP such as
when a request is smaller than path MTU and is therefore sent over UDP
but the response exceeds the MTU size - how do you deliver the
response then?.

If there is ever a SIP 3.0, I believe there is enough consensus that
it'll not support UDP transport.

--
Raj
On Mon, Mar 10, 2008 at 9:29 PM, Philipp von Klitzing
<klitzing at pool.informatik.rwth-aachen.de> wrote:

Quote:

Hi!

Quote:

What is the logic of them using SIP over TCP? Is this a broad industry
trend? Or just the latest attempt to get around SIP/NAT issues?

I remember a quote of Henning Schulzrinne where he states that having
designed SIP with UDP in mind was the biggest mistake he (and Mark
Handle?) were to be found guilty of. I am not sure if this is what's
driving Microsoft's decisions, my guess is that this is/was mostly driven
by security reasons (and the new focus of Microsoft on security aspects).

Cheers, Philipp

* Taken from http://www.faqs.org/rfcs/rfc4168.html:

3.1. Advantages over UDP

All the advantages that SCTP has over UDP regarding SIP transport are
also shared by TCP. Below, there is a list of the general advantages
that a connection-oriented transport protocol such as TCP or SCTP has
over a connection-less transport protocol such as UDP.

Fast Retransmit: SCTP can quickly determine the loss of a packet,
because of its usage of SACK and a mechanism that sends SACK
messages faster than normal when losses are detected. The result
is that losses of SIP messages can be detected much faster than
when SIP is run over UDP (detection will take at least 500 ms, if
not more). Note that TCP SACK exists as well, and TCP also has a
fast retransmit option. Over an existing connection, this results
in faster call setup times under conditions of packet loss, which
is very desirable. This is probably the most significant
advantage of SCTP for SIP transport.

Congestion Control: SCTP maintains congestion control over the entire
association. For SIP, this means that the aggregate rate of
messages between two entities can be controlled. When SIP is run
over TCP, the same advantages are afforded. However, when run
over UDP, SIP provides less effective congestion control. This is
because congestion state (measured in terms of the UDP retransmit
interval) is computed on a transaction-by-transaction basis,
rather than across all transactions. Thus, congestion control
performance is similar to opening N parallel TCP connections, as
opposed to sending N messages over one TCP connection.

Transport-Layer Fragmentation: SCTP and TCP provide transport-layer
fragmentation. If a SIP message is larger than the MTU size, it
is fragmented at the transport layer. When UDP is used,
fragmentation occurs at the IP layer. IP fragmentation increases
the likelihood of having packet losses and makes NAT and firewall
traversal difficult, if not impossible. This feature will become
important if the size of SIP messages grows dramatically.

* Quote from http://tools.ietf.org/html/draft-jennings-sip-dtls-01:

There has been considerable discussion of why SIP needs DTLS when we
have TLS. This is the wrong question. The right question is why SIP
has UDP and TCP (not to mention SCTP). There are two reasons for
believing that UDP is likely to be an important protocol in SIP for
the foreseeable future.

o In theory, there is no problem building systems that terminate a
million TCP connections on a single host. In practice, the common
operating systems used for building SIP aggregation devices make
this impossible. To date, no one has demonstrated terminating
over 100k SIP TCP connections to a single host. Doing that many
connections with UDP has not been difficult.

o If we want to talk about "running code" for SIP, it's UDP. Unless
UDP is deprecated for SIP, it is important to provide a reasonable
level of security for it.

_______________________________________________
-- Bandwidth and Colocation Provided by http://www.api-digital.com --

asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
http://lists.digium.com/mailman/listinfo/asterisk-users

milton at calnek.com
Guest

Posted: Tue Mar 11, 2008 9:15 am Post subject: [asterisk-users] Microsoft Office Communications Server

Tzafrir Cohen wrote:

Quote:

TV sets and such are simple enough. But when the device gets more
sofficticated then, yes: reboot tends to become a first reaction.

You say "first reaction" like there's some other choice with Windows.

Quote:

Right. Asterisk never crashes. Asterisk is completely solid.

It's amazing what happens when you say "Sure, look under the hood!!"
The free software community is full of examples of open source being
more stable with fewer bugs than their closed source, commercial
competitors.

--
Milton Calnek BSc, A/Slt(Ret.)
milton at calnek.com
306-717-8737
--
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.

senad at bicom.us
Guest

Posted: Tue Mar 11, 2008 9:24 am Post subject: [asterisk-users] Microsoft Office Communications Server

Milton Calnek wrote:

Quote:

Tzafrir Cohen wrote:

Quote:

TV sets and such are simple enough. But when the device gets more
sofficticated then, yes: reboot tends to become a first reaction.

You say "first reaction" like there's some other choice with Windows.

Quote:

Right. Asterisk never crashes. Asterisk is completely solid.

Of course it crashes... in wrongs hands Smile

Senad

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