Subject: RE: [Sip] Primary vs. backup

From: "Christer Holmberg \(JO/LMF\)" <[email-masked]>
Date: Mon, 29 May 2006 08:32:43 +0200

Hi, 

>>Unfortunately, we really do need to solve the problem of locating  
>>Outbound-capable servers using DNS records.  But do we need to specify

>>exactly which servers a UA must use, beyond the rather general  
>>preference and balancing rules of RFC 3263?
>dale, this is exactly what i have proposed in two or three emails to
this list already.  since i don't remember anyone opposing, it would be
nice if the 
>authors outbound would issue a new version where the primary/backup
distinction has been eliminated.

[CHH] This may be related to the discussion we had a while ago (thread
subject: "Outbound: Multiple flows and forking"). At that time I
proposed text saying "For reliability or load balancing reasons, the UA
MAY send REGISTER to more than one outbound proxy...". At that point we
also discussed whehter "primary and secondary" is the correct wording in
the first place. [/CHH]

>>At this point, an idea occurs to me that must have already been  >
considered and rejected -- Why not have the UA attempt to register  
>>using the 3263 rules, but specifying "Requires: outbound"?  That will
> automatically exclude servers that do not support Outbound.
>>The only limitation would be that a UA using Outbound would see the
same  > priority relationships between the servers that a non-Outbound
UA  
>>would see.
>yes, it would mean lots of redirects by the proxies.

[CHH] I think that depends pretty much on how the operators build and
design their networks. [/CHH]

Regards,

Christer

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Use sip-implementors@cFrom [email-masked] Mon May 29 02:48:40 2006
Content-class: urn:content-classes:message
Subject: RE: [Sip] Primary vs. backup
Date: Mon, 29 May 2006 08:32:43 +0200
From: "Christer Holmberg \(JO/LMF\)" <[email-masked]>
To: "Juha Heinanen" <[email-masked]>,
	"Dale R. Worley" <[email-masked]>
Cc: Sip <[email-masked]>

Hi, 

>>Unfortunately, we really do need to solve the problem of locating  
>>Outbound-capable servers using DNS records.  But do we need to specify

>>exactly which servers a UA must use, beyond the rather general  
>>preference and balancing rules of RFC 3263?
>dale, this is exactly what i have proposed in two or three emails to
this list already.  since i don't remember anyone opposing, it would be
nice if the 
>authors outbound would issue a new version where the primary/backup
distinction has been eliminated.

[CHH] This may be related to the discussion we had a while ago (thread
subject: "Outbound: Multiple flows and forking"). At that time I
proposed text saying "For reliability or load balancing reasons, the UA
MAY send REGISTER to more than one outbound proxy...". At that point we
also discussed whehter "primary and secondary" is the correct wording in
the first place. [/CHH]

>>At this point, an idea occurs to me that must have already been  >
considered and rejected -- Why not have the UA attempt to register  
>>using the 3263 rules, but specifying "Requires: outbound"?  That will
> automatically exclude servers that do not support Outbound.
>>The only limitation would be that a UA using Outbound would see the
same  > priority relationships between the servers that a non-Outbound
UA  
>>would see.
>yes, it would mean lots of redirects by the proxies.

[CHH] I think that depends pretty much on how the operators build and
design their networks. [/CHH]

Regards,

Christer

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

---

From: Juha Heinanen <[email-masked]>
Date: Mon, 29 May 2006 09:42:45 +0300

> design their networks. [/CHH]

the idea is that local clients use outbound proxies and others would use
non-outbound proxies.  you can play with probabilities and DNS record
priorities, but if about half of request come from local clients and
half from non-local sources, i don't see how you can avoid about 50 % of
request initially ending up to wrong proxy.

-- juha

s.columbia.edu for questions on current sip
Use [email-masked] for new developments on the application of sip

---

From: Juha Heinanen <[email-masked]>
Date: Mon, 29 May 2006 09:42:45 +0300

-- juha