Re: [OSPF] OSPFv2 SR draft

[Chris Bowers <[e-mail]>]

Peter,

Please share the updated text that you plan to use with the WG, since this is a reasonably significant clarification.  

Thanks,
Chris

-----Original Message-----
From: Peter Psenak [mailto:[e-mail]] 
Sent: Tuesday, August 16, 2016 10:02 AM
To: Chris Bowers <[e-mail]>; OSPF List <[e-mail]>
Subject: Re: [OSPF] OSPFv2 SR draft

Hi Chris,

I'll update the draft along those lines.

thanks,
Peter


On 16/08/16 16:02 , Chris Bowers wrote:
> Peter,
>
> I suggest changing the paragraph to read as below to make this clearer.
>
> =====
>     The SR-Algorithm Sub-TLV is optional.  It MAY only be advertised once
>     in the Router Information Opaque LSA.  If the SID/Label Range TLV, as
>     defined in Section 3.2, is advertised, then the SR-Algorithm TLV MUST
>     also be advertised.  If a router C advertises a Prefix-SID sub-TLV for algorithm X
>     but does not advertise the SR-Algorithm Sub-TLV with algorithm X, then
>     a router receiving that advertisement MUST ignore the Prefix-SID
>     advertisement from router C.  If router B does not advertise the
>     SR-Algorithm TLV for algorithm X, then other routers should not
>     forward traffic destined for a prefix-SID for algorithm X advertised by
>     some router D using a path that would require router B to forward traffic using
>     algorithm X.
> =====
>
> Thanks,
> Chris
>
>
>
> -----Original Message-----
> From: Peter Psenak [mailto:[e-mail]]
> Sent: Monday, August 15, 2016 6:40 AM
> To: Chris Bowers <[e-mail]>; OSPF List <[e-mail]>
> Subject: Re: [OSPF] OSPFv2 SR draft
>
> Hi Chris,
>
> sorry for the delay, I was on PTO during last two weeks.
> Please see inline:
>
> On 03/08/16 16:45 , Chris Bowers wrote:
>> Peter,
>>
>> Taking a looking at the whole paragraph into this sentence was added, 
>> I am not sure how to interpret it.
>>
>>      The SR-Algorithm Sub-TLV is optional.  It MAY only be advertised once
>>      in the Router Information Opaque LSA.  If the SID/Label Range TLV, as
>>      defined in Section 3.2, is advertised, then the SR-Algorithm TLV MUST
>>      also be advertised.  If the SR-Algorithm TLV is not advertised by the
>>      node, such node is considered as not being segment routing capable.
>>
>> Is this sentence intended to imply that if a router does not 
>> advertise the SR-Algorithm TLV including algorithm X, then any 
>> prefix-SIDs for algorithm X advertised by that router will be ignored by other routers?
>
> in OSPF we do not have the SR capability TLV. We use SR-Algorithm TLV 
> for that purpose. So if a router does not advertise the SR-Algorithm 
> TLV for algorithm X, other routers should not send any SR traffic 
> using SIDs that were advertised for algorithm X.
>
> If the router does not advertise any SR Algorithm TLV, then the node 
> is not SR capable and no SR traffic should be forwarded to such a node.
>
> thanks,
> Peter
>
>
>>
>> If this is the intention, then it would be better to state is more explicitly.
>>
>> If not, then the intended meaning should be clarified.
>>
>> Thanks,
>> Chris
>>
>>
>> -----Original Message-----
>> From: OSPF [mailto:[e-mail]] On Behalf Of Peter Psenak
>> Sent: Friday, July 22, 2016 3:30 AM
>> To: OSPF List <[e-mail]>
>> Subject: [OSPF] OSPFv2 SR draft
>>
>> Hi All,
>>
>> following text has been added in the latest revision of the OSPFv2 SR 
>> draft, section 3.1.
>>
>> "If the SR-Algorithm TLV is not advertised by node, such node is 
>> considered as not being segment routing capable."
>>
>> Please let us know if there are any concerns regarding this addition.
>>
>> thanks,
>> Peter
>>
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>
> .
>