Peter,
>
>> I would think that we should have "route type" as in Extended prefix TLV
>> instead of just having a bit indicating "inter area"
>
> route-type would be misleading for range, as single range can include
> prefixes of various types (intra, inter, external). We have discussed
> this between authors and we agreed route-type is not the right way.
>
> <Shraddha> The prefix range TLV is carried in Extended prefix LSA which is
> based on scope of flooding.
> If we combine intra/inter/external in the prefix
> range TLV, what scope is used for flooding the extended prefix LSA?
prefix range is used for SR mapping server to optimize the SID
advertisement. Prefix range as such does not need to have a route type,
because it is not advertising a reachability. One can use domain wide
flooding for certain external prefix, but use regular inter-area
distribution for prefix range that is covering the external prefix.
<Shraddha> Combining the different route types in the prefix range TLV looks
very complex.
How practical it is in a real deployment to get a
prefix range that covers through intra/inter/external route types?
In my opinion, it is adding unnecessary complexity into
the protocol.
If a prefix range covers intra and inter area routes
would the IA flag be set?
Would this prefix range be propagated from backbone area
to non-backbone area?
If some prefix range contains a mix of inter and external
how's the inter area prefix SIDs
Propagated into NSSA area and external ones blocked?
Keeping the prefix ranges confined within route types
would make it much more simple.
Rgds
Shraddha
-----Original Message-----
From: Peter Psenak [mailto:ppse...@cisco.com]
Sent: Wednesday, December 03, 2014 2:01 PM
To: Shraddha Hegde; draft-ietf-ospf-segment-routing-extensi...@tools.ietf.org
Cc: OSPF WG List
Subject: Re: draft-ietf-ospf-segment-routing-extensions-03
Shraddha,
please see inline:
On 12/3/14 06:10 , Shraddha Hegde wrote:
> Peter,
>
> <Snipped to open points>
>
>> Shouldn't each node in broadcast link originate LAN adj-SID
>> and advertise label to all other nodes on the link?
>
> For the adjacency to DR, Adj-SID Sub-TLV is used. For the adjacency to
> non-DR LAN Adj-SID Sub-TLV is used. It's done all all nodes on the LAN.
>
> <Shraddha> Is there a specific reason to advertise adj-sid for the DR and LAN
> adj-sid for non-DR?
> Is it because the Neighbor-ID is already part of
> Extended link TLV and we are saving 4 bytes?
for adjacency on 2p2 link and adjacency to DR, link-type and link-id in
Extended link TLV is used. For non-DR case, we need to describe the neighbor by
neighbor-id, so we needed a new sub-TLV to do that.
>
>
>> I would think that we should have "route type" as in Extended prefix TLV
>> instead of just having a bit indicating "inter area"
>
> route-type would be misleading for range, as single range can include
> prefixes of various types (intra, inter, external). We have discussed
> this between authors and we agreed route-type is not the right way.
>
> <Shraddha> The prefix range TLV is carried in Extended prefix LSA which is
> based on scope of flooding.
> If we combine intra/inter/external in the prefix
> range TLV, what scope is used for flooding the extended prefix LSA?
prefix range is used for SR mapping server to optimize the SID
advertisement. Prefix range as such does not need to have a route type,
because it is not advertising a reachability. One can use domain wide
flooding for certain external prefix, but use regular inter-area
distribution for prefix range that is covering the external prefix.
thanks,
Peter
>
>
> Rgds
> Shraddha
>
> -----Original Message-----
> From: Peter Psenak [mailto:ppse...@cisco.com]
> Sent: Tuesday, December 02, 2014 10:39 PM
> To: Shraddha Hegde; draft-ietf-ospf-segment-routing-extensi...@tools.ietf.org
> Cc: OSPF WG List
> Subject: Re: draft-ietf-ospf-segment-routing-extensions-03
>
> Shraddha,
>
> please see inline:
>
> On 12/2/14 17:50 , Shraddha Hegde wrote:
>> Authors,
>> Some comments on the draft.
>>
>> 1. The draft refers to the various use cases in the use case document
>> in I-D.filsfils-rtgwg-segment-routing. It's useful to mention the
>> section of the use case draft which is applicable for each reference
>> instead of giving generic reference.
>
> sure, we can add that.
>
>> 2. Section 7.2 LAN Adj-sid sub TLV:
>>
>> Based on the description of the text it appears that the LAN AdjSID
>> Sub TLV can contain multiple neighbor-ID /SID pairs based on the nodes
>> attached to a broadcast network. The TLV diagram should depict
>> carrying multiple such pairs.
>
> no. LAN AdjSID Sub TLV only advertises a adj-SID for a single neighbor.
> If you have more non-DR neighbors, you need to advertise multiple LAN Adj-SID
> Sub-TLVs.
>
>
>> "It is used to advertise a SID/Label for an
>> adjacency to a non-DR node on a broadcast or NBMA network."
>> Does the above statement mean only DR originates the LAN-Adj SIDand
>> advertises label to non-DR nodes?
>
> no.
>
>> Shouldn't each node in broadcast link originate LAN adj-SID and
>> advertise label to all other nodes on the link?
>
> For the adjacency to DR, Adj-SID Sub-TLV is used. For the adjacency to
> non-DR LAN Adj-SID Sub-TLV is used. It's done all all nodes on the LAN.
>
>>
>> 3. Adj-Sid sub TLV section 7.1:
>>
>> Description of V-flag mentions Prefix-SID, it should be changed to Adj-SID.
>
> good catch, will correct.
>
>>
>> 4. Section 4: Extended prefix range TLV is very similar to Extended
>> prefix TLV just that it has additional range associated with it.
>
> yes, that is correct.
>
>>
>> I would think that we should have "route type" as in Extended prefix TLV
>> instead of just having a bit indicating "inter area"
>
> route-type would be misleading for range, as single range can include
> prefixes of various types (intra, inter, external). We have discussed
> this between authors and we agreed route-type is not the right way.
>
> thanks,
> Peter
>
>> Rgds
>> Shraddha
>
> .
>
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