Regd encoding of ISIS SRMS range inside BGP-LS
"Ketan Talaulikar (ketant)" <[email protected]>
| Newsgroups | gmane.ietf.isis |
|---|---|
| Message-ID | <d7a9067191e64b34bf3d53c9b7c699fd__31343.9978905537$1497446569$gmane$org@XCH-ALN-008.cisco.com> |
Hello All,
Needed some clarification from the authors and implementers of BGP-LS on Sec 3.4 of the https://tools.ietf.org/html/draft-ietf-idr-bgp-ls-segment-routing-ext-01#page-26
It currently states ...
3.4. Advertisement of a range of IS-IS SR bindings
The advertisement of a range of IS-IS SR bindings has following
rules:
In IS-IS the Mapping Server binding ranges are advertised using
the Binding TLV. The IS-IS Binding TLV is encoded in the BGP-LS
Prefix Attribute Range TLV as defined in Section 2.3.5 using the
Binding Sub-TLV as defined in Section 2.3.6. The flags in the
Range TLV are all set to zero on transmit and ignored on
reception. The range value from the original IS-IS Binding TLV is
encoded in the Range TLV "Range" field.
My understanding what that the encoding for ISIS is done with Range TLV + Prefix-SID sub-TLV (very similar to how it is specified in Sec 3.3 for OSPF). However the language is indirectly referring to the Prefix-SID sub-TLV by saying "using the Binding Sub-TLV".
This may give an impression that the encoding for ISIS is done as Range TLV + Binding TLV + Prefix-SID sub-TLV and differently than done for OSPF. It would be clearer if the ISIS sec 3.4 were to also use similar language as OSPF sec 3.3. Would like to propose something like below:
3.4. Advertisement of a range of IS-IS SR bindings
The advertisement of a range of IS-IS SR bindings has following
rules:
In IS-IS the Mapping Server binding ranges are advertised using
the IS-IS Binding TLV
([I-D.ietf-isis-segment-routing-extensions]). The IS-IS Binding
TLV is encoded in the BGP-LS Prefix Attribute Range TLV as defined
in Section 2.3.4.
The flags in the Range TLV are all set to zero on transmit and
ignored on reception. The range value from the original IS-IS
Binding TLV is encoded in the Range TLV "Range" field. The
Prefix-SID from the original ISIS Prefix SID Sub-TLV is encoded
using the BGP-LS Prefix Attribute Prefix-SID as defined in
Section 2.3.1 with the flags set according to the definition in
[I-D.ietf-isis-segment-routing-extensions]
I would also like to check if anyone has implemented the encoding of ISIS SRMS range using the Binding SID TLV.
Thanks,
Ketan