Shraddha,
On 12/5/14 05:52 , Shraddha Hegde wrote:
Peter,
<snipped>
Would this prefix range be propagated from backbone
area to non-backbone area?
yes, SRMS range advertisements will be propagated between areas if LSA type 10
is used for the advertisement.
<Shraddha> You mean area scope (type 10) LSAs will be flooded across area
boundary? Or you mean they will be
Re-originated at the boundary and if AS scope LSA (type
11) they will be flooded across the boundary?
type 10 will be reoriginated, type 11 will be flooded across.
Keeping the prefix ranges confined within route types
would make it much more simple.
true, but it will make the deployment harder.
<Shraddha> OK. I see your point.
I think the document needs to capture the information that the prefix range can
have different route-types covered.
It wasn't clear from reading the document. Probably an "elements of procedure"
section is required for the prefix range TLV
To cover the flooding scope and other aspects.
sure.
One more point to be mentioned is that if there is a prefix range TLV that
covers a certain prefix and there is also a prefix SID
For the same prefix , then the prefix SID should be considered and the SID in
the prefix range should be ignored.
agreed. Will add that to the doc.
thanks,
Peter
Rgds
Shraddha
-----Original Message-----
From: Peter Psenak [mailto:[email protected]]
Sent: Thursday, December 04, 2014 11:15 PM
To: Shraddha Hegde; [email protected]
Cc: OSPF WG List
Subject: Re: draft-ietf-ospf-segment-routing-extensions-03
Shraddha,
On 12/4/14 17:45 , Shraddha Hegde wrote:
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?
Imagine you want to advertise a SIDs for a range 192.0.2.1, Prefix Length 32,
Range Size 255. Out of that range individual /32 prefixes can be of different
route-types. Prefix range does not have a route-type.
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?
IA flag has nothing to do with the route-type. IA flag means that the range
advertisement has bean 'leaked' between areas and is used to prevent redundant
leaking.
Would this prefix range be propagated from backbone
area to non-backbone area?
yes, SRMS range advertisements will be propagated between areas if LSA type 10
is used for the advertisement.
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?
that is not a problem. You may not have external prefix in NSSA area, but the
range can still cover such external prefix. In such case the SID for the
external prefix will never be used in NSSA area.
Keeping the prefix ranges confined within route types
would make it much more simple.
true, but it will make the deployment harder.
thanks,
Peter
Rgds
Shraddha
-----Original Message-----
From: Peter Psenak [mailto:[email protected]]
Sent: Wednesday, December 03, 2014 2:01 PM
To: Shraddha Hegde;
[email protected]
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:[email protected]]
Sent: Tuesday, December 02, 2014 10:39 PM
To: Shraddha Hegde;
[email protected]
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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