Subject: RE: [Sipping] Draft: Functions of Current SBCs

From: "Parolkar, Satish" <[email-masked]>
Date: Wed, 2 Mar 2005 09:20:52 -0600

I agree functions at network borders are business relationships. Should
SBC functions be discussed in IETF forum at all?

I don't think the issue is of missing functionality in the protocols or
lack of standardization. I believe the issue may be of policy setting
between two VoIP networks. 

For example, consider the issue of security....There are many ways that
two service provider domains can secure their networks.

(a) Should Security be established using IPSec between the Edge Routers
so that VoIP call transport is secure across the public IP network? 
OR 
(b) Should security be established between proxy servers using TLS to
secure SIP signaling? Do networks feel secure if only signaling is
protected?
OR
(c) Should IP end points based on their needs encrypt voice using sRTP.
Who should be responsible to secure voice the end customer or the
service provider?
OR
(d) Should networks use Topology Hiding and strip or encrypt some of the
SIP headers using Session Border Controllers that act as B2BUA.
OR
(e) Should networks use Media Relay to terminate and re-create RTP
streams at the edge of the networks using Session Border Controllers.

Similarly, in regards to QOS. Two networks need to establish policies to
determine if they want to use RSVP or DIffServ. Use MPLS VPN with QOS
etc to establish QoS. Should Session Admission Control be adopted? Once
again the protocols are established, it is just a matter of policy and
agreement based on evaluations as to which approach helps support voice
quality.

The SIP protocol, IPSec, TLS are all standardized. Unfortunately there
are too many standards. So the issue is not at all about
standardization. It is about the policy two networks want to establish
to ensure secure communications and that is a business relationship.

The issue that needs to be addressed is what security and QoS policy is
optimum to provide secure and quality communications across peering
domains? Is there a forum that discusses the "policies" to establish
secure and quality VoIP communications across different network domains?

Satish
SBC Labs.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Jonathan Rosenberg
Sent: Wednesday, March 02, 2005 3:38 AM
To: Tom Taylor
Cc: sipping
Subject: Re: [Sipping] Draft: Functions of Current SBCs

Ultimately, required functions at a border depend on the business
relationships between those entities. Even for carrier-carrier
relationships, we have lots of different types: consumer voip providers
connecting to termination providers, consumer providers peering with
other consumer providers, wholesalers peering with other wholesalers,
and so on. I agree with Tom that there is a bigger gulf in the nature of
the relationships when you go from subscriber-carrier to
carrier-carrier, but its just a matter of degree.

I think that an attempt to classify the breadth of business
relationships between entities is ultimately futile. Since I don't
believe we need to standardize what an SBC is, we don't need to
standardize what a client facing SBC is vs. an inter-carrier SBC. We do
need to consider whether any of the relationships folks have seen in the
market have pushed functions into SBC products that are solving problems
not currently considered by existing standards.

-Jonathan R.

Tom Taylor wrote:

> Two possible distinctions that I see, but maybe we could position them

> in a spectrum of classifications of borders:
>  (1) Trust models are likely to differ for inter-carrier as opposed to

> subscriber-carrier handoff.
>  (2) QOS model is more likely to be governed by SLA when going 
> inter-carrier. Here, for sure, the enterprise-carrier boundary falls 
> somewhere between.
> 
> Ben Campbell wrote:
> 
>> While I normally hesitate to disagree with Henry, I think this 
>> taxonomy talks more about business models than anything technical. I 
>> have personally built out SIP networks where no "carrier" in the 
>> sense of a VoIP (or other media) provider existed at all. (I assume 
>> you are not including an IP carrier that is not somehow participating

>> in the VoIP stuff other than moving bits around--if this assumption 
>> is incorrect than disregard my comment).
>>
>> If we do need to distinguish these two SBC roles, I suggest we 
>> examine what makes them different, not just what sort of company is 
>> deploying them.
>>
>> On Feb 27, 2005, at 3:00 PM, [email-masked] wrote:
>>
>>> Two names for two very different devices: In the carrier network or 
>>> at the perimeter of the customer location.
>>>  
>>> The location changes many security aspects (we need to specify 
>>> which) and also the media performance, as well as bandwidth
consumption.
>>> Multi-homing of customer networks is an issue here as well.
>>>  
>>> Henry
>>>
> ...
> 
> _______________________________________________
> Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
> This list is for NEW development of the application of SIP Use 
> [email-masked] for questions on current sip Use 
> [email-masked] for new developments of core SIP
> 

-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Director, Service Provider VoIP Architecture   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
http://www.jdrosen.net                         PHONE: (973) 952-5000
http://www.cisco.com

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP Use
[email-masked] for questions on current sip Use
[email-masked] for new developments of core SIP

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: Tom Taylor <[email-masked]>
Date: Wed, 02 Mar 2005 10:46:30 -0500

Nice formulation of policy issues.  I can answer your final question: the 
Multi-Service Forum (MSF) is working on the sort of policies of which you speak.

...

---

From: [email-masked]
Date: Wed, 2 Mar 2005 11:11:13 -0500

So if I want to make a VoIP + IM + FTP call from Dallas to Tokyo, how many
agreements and policies will come into play?

Henry 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Parolkar, Satish
Sent: Wednesday, March 02, 2005 10:21 AM
To: Jonathan Rosenberg; Tom Taylor
Cc: sipping
Subject: RE: [Sipping] Draft: Functions of Current SBCs

I agree functions at network borders are business relationships. Should SBC
functions be discussed in IETF forum at all?

I don't think the issue is of missing functionality in the protocols or lack
of standardization. I believe the issue may be of policy setting between two
VoIP networks. 

For example, consider the issue of security....There are many ways that two
service provider domains can secure their networks.

(a) Should Security be established using IPSec between the Edge Routers so
that VoIP call transport is secure across the public IP network? 
OR
(b) Should security be established between proxy servers using TLS to secure
SIP signaling? Do networks feel secure if only signaling is protected?
OR
(c) Should IP end points based on their needs encrypt voice using sRTP.
Who should be responsible to secure voice the end customer or the service
provider?
OR
(d) Should networks use Topology Hiding and strip or encrypt some of the SIP
headers using Session Border Controllers that act as B2BUA.
OR
(e) Should networks use Media Relay to terminate and re-create RTP streams
at the edge of the networks using Session Border Controllers.

Similarly, in regards to QOS. Two networks need to establish policies to
determine if they want to use RSVP or DIffServ. Use MPLS VPN with QOS etc to
establish QoS. Should Session Admission Control be adopted? Once again the
protocols are established, it is just a matter of policy and agreement based
on evaluations as to which approach helps support voice quality.

The SIP protocol, IPSec, TLS are all standardized. Unfortunately there are
too many standards. So the issue is not at all about standardization. It is
about the policy two networks want to establish to ensure secure
communications and that is a business relationship.

The issue that needs to be addressed is what security and QoS policy is
optimum to provide secure and quality communications across peering domains?
Is there a forum that discusses the "policies" to establish secure and
quality VoIP communications across different network domains?

Satish
SBC Labs.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Jonathan Rosenberg
Sent: Wednesday, March 02, 2005 3:38 AM
To: Tom Taylor
Cc: sipping
Subject: Re: [Sipping] Draft: Functions of Current SBCs

Ultimately, required functions at a border depend on the business
relationships between those entities. Even for carrier-carrier
relationships, we have lots of different types: consumer voip providers
connecting to termination providers, consumer providers peering with other
consumer providers, wholesalers peering with other wholesalers, and so on. I
agree with Tom that there is a bigger gulf in the nature of the
relationships when you go from subscriber-carrier to carrier-carrier, but
its just a matter of degree.

I think that an attempt to classify the breadth of business relationships
between entities is ultimately futile. Since I don't believe we need to
standardize what an SBC is, we don't need to standardize what a client
facing SBC is vs. an inter-carrier SBC. We do need to consider whether any
of the relationships folks have seen in the market have pushed functions
into SBC products that are solving problems not currently considered by
existing standards.

-Jonathan R.

consumption.

---

From: Henning Schulzrinne <[email-masked]>
Date: Wed, 02 Mar 2005 11:20:19 -0500

None. They'll be using Skype instead.