draft-ietf-mpls-crldp-unnum-09.txt   draft-ietf-mpls-crldp-unnum-10.txt 
Network Working Group Kireeti Kompella Network Working Group Kireeti Kompella
Internet Draft Juniper Networks Internet Draft Juniper Networks
Expiration Date: April 2003 Yakov Rekhter Expiration Date: June 2003 Yakov Rekhter
Juniper Networks Juniper Networks
Alan Kullberg Alan Kullberg
NetPlane Systems NetPlane Systems
Signalling Unnumbered Links in CR-LDP Signalling Unnumbered Links in CR-LDP
draft-ietf-mpls-crldp-unnum-09.txt draft-ietf-mpls-crldp-unnum-10.txt
1. Status of this Memo 1. Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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unnumbered links because the current signalling doesn't provide a way unnumbered links because the current signalling doesn't provide a way
to indicate an unnumbered link in its Explicit Route Objects. This to indicate an unnumbered link in its Explicit Route Objects. This
document proposes simple procedures and extensions that allow CR-LDP document proposes simple procedures and extensions that allow CR-LDP
signalling [CR-LDP] to be used with unnumbered links. signalling [CR-LDP] to be used with unnumbered links.
5. Link Identifiers 5. Link Identifiers
An unnumbered link has to be a point-to-point link. An LSR at each An unnumbered link has to be a point-to-point link. An LSR at each
end of an unnumbered link assigns an identifier to that link. This end of an unnumbered link assigns an identifier to that link. This
identifier is a non-zero 32-bit number that is unique within the identifier is a non-zero 32-bit number that is unique within the
scope of the LSR that assigns it. The IS-IS and/or OSPF and RSVP scope of the LSR that assigns it. If one is using OSPF or ISIS as the
modules on an LSR must agree on the identifiers. IGP in support of traffic engineering, then the IS-IS and/or OSPF and
CR-LDP modules on an LSR must agree on the identifiers.
There is no a priori relationship between the identifiers assigned to There is no a priori relationship between the identifiers assigned to
a link by the LSRs at each end of that link. a link by the LSRs at each end of that link.
LSRs at the two end points of an unnumbered link exchange with each LSRs at the two end points of an unnumbered link exchange with each
other the identifiers they assign to the link. Exchanging the other the identifiers they assign to the link. Exchanging the
identifiers may be accomplished by configuration, by means of a identifiers may be accomplished by configuration, by means of a
protocol such as LMP ([LMP]), by means of RSVP/CR-LDP (especially in protocol such as LMP ([LMP]), by means of CR-LDP (especially in the
the case where a link is a Forwarding Adjacency, see below), or by case where a link is a Forwarding Adjacency, see below), or by means
means of IS-IS or OSPF extensions ([ISIS-GMPLS], [OSPF-GMPLS]). of IS-IS or OSPF extensions ([ISIS-GMPLS], [OSPF-GMPLS]).
Consider an (unnumbered) link between LSRs A and B. LSR A chooses an Consider an (unnumbered) link between LSRs A and B. LSR A chooses an
idenfitier for that link. So is LSR B. From A's perspective we refer idenfitier for that link. So is LSR B. From A's perspective we refer
to the identifier that A assigned to the link as the "link local to the identifier that A assigned to the link as the "link local
identifier" (or just "local identifier"), and to the identifier that identifier" (or just "local identifier"), and to the identifier that
B assigned to the link as the "link remote identifier" (or just B assigned to the link as the "link remote identifier" (or just
"remote identifier"). Likewise, from B's perspective the identifier "remote identifier"). Likewise, from B's perspective the identifier
that B assigned to the link is the local identifier, and the that B assigned to the link is the local identifier, and the
identifier that A assigned to the link is the remote identifier. identifier that A assigned to the link is the remote identifier.
In the context of this document the term "Router ID" refers to the In the context of this document the term "Router ID" means a stable
"Router Address" as defined in [OSPF-TE], or "Traffic Engineering IP address of an LSR that is always reachable if there is any
Router ID" as defined in [ISIS-TE]. connectivity to the LSR. This is typically implemented as a "loopback
address"; the key attribute is that the address does not become
unusable if an interface on the LSR is down. In some case this value
will need to be configured. If one is using OSPF or ISIS as the IGP
in support of traffic engineering, then it is RECOMMENDED to set the
Router ID to the "Router Address" as defined in [OSPF-TE], or
"Traffic Engineering Router ID" as defined in [ISIS-TE].
This section is equally applicable to the case of unnumbered This section is equally applicable to the case of unnumbered
component links (see [LINK-BUNDLE]). component links (see [LINK-BUNDLE]).
6. Unnumbered Forwarding Adjacencies 6. Unnumbered Forwarding Adjacencies
If an LSR that originates an LSP advertises this LSP as an unnumbered If an LSR that originates an LSP advertises this LSP as an unnumbered
Forwarding Adjacency in IS-IS or OSPF (see [LSP-HIER]), or the LSR Forwarding Adjacency in IS-IS or OSPF (see [LSP-HIER]), or the LSR
uses the Forwarding Adjacency formed by this LSP as an unnumbered uses the Forwarding Adjacency formed by this LSP as an unnumbered
component link of a bundled link (see [LINK-BUNDLE]), the LSR MUST component link of a bundled link (see [LINK-BUNDLE]), the LSR MUST
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Interface ID field of the Reverse Interface ID TLV (for the Interface ID field of the Reverse Interface ID TLV (for the
definition of Reverse Interface ID TLV see below). The LSR that is a definition of Reverse Interface ID TLV see below). The LSR that is a
tail-end of that Forwarding Adjacency sets the link local identifier tail-end of that Forwarding Adjacency sets the link local identifier
for that link to the value that the LSR allocates to that Forwarding for that link to the value that the LSR allocates to that Forwarding
Adjacency, and the link remote identifier to the value carried in the Adjacency, and the link remote identifier to the value carried in the
Interface ID field of the Forward Interface ID TLV (for the Interface ID field of the Forward Interface ID TLV (for the
definition of Forward Interface ID see below). definition of Forward Interface ID see below).
6.1. LSP_TUNNEL_INTERFACE_ID TLV 6.1. LSP_TUNNEL_INTERFACE_ID TLV
The LSP_TUNNEL_INTERFACE ID TLV has Type to be determined by IETF The LSP_TUNNEL_INTERFACE ID TLV has Type to be assigned by IANA and
consensus and length 8. The format is given below. length 8. The format is given below.
Figure 1: LSP_TUNNEL_INTERFACE_ID TLV Figure 1: LSP_TUNNEL_INTERFACE_ID TLV
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type | Length | |0|0| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSR's Router ID | | LSR's Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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MAPPING message. In the former case, we call it the "Forward MAPPING message. In the former case, we call it the "Forward
Interface ID" for that LSP; in the latter case, we call it the Interface ID" for that LSP; in the latter case, we call it the
"Reverse Interface ID" for the LSP. "Reverse Interface ID" for the LSP.
7. Signalling Unnumbered Links in Explicit Route TLV 7. Signalling Unnumbered Links in Explicit Route TLV
A new Type of ER-Hop TLV of the Explicit Route TLV is used to specify A new Type of ER-Hop TLV of the Explicit Route TLV is used to specify
unnumbered links. This Type is called Unnumbered Interface ID, and unnumbered links. This Type is called Unnumbered Interface ID, and
has the following format: has the following format:
The Type is assigned by IANA, and the Length is 12. The L bit is set
to indicate a loose hop, and cleared to indicate a strict hop.
The Interface ID is the identifier assigned to the link by the LSR
specified by the router ID.
Figure 2: Unnumbered Interface ID Figure 2: Unnumbered Interface ID
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type = 0x0805 | Length = 12 | |0|0| Type | Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Reserved | |L| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router ID | | Router ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID (32 bits) | | Interface ID (32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type is 0x0805 (Unnumbered Interface ID) and the Length is 12.
The L bit is set to indicate a loose hop, and cleared to indicate a
strict hop.
The Interface ID is the identifier assigned to the link by the LSR
specified by the router ID.
7.1. Processing the IF_ID TLV 7.1. Processing the IF_ID TLV
When an LSR receives a REQUEST message containing the IF_ID TLV (see When an LSR receives a REQUEST message containing the IF_ID TLV (see
[GMPLS-CRLDP]) with the IF_INDEX TLV, the LSR processes this TLV as [GMPLS-CRLDP]) with the IF_INDEX TLV, the LSR processes this TLV as
follows. The LSR must have information about the identifiers assigned follows. The LSR must have information about the identifiers assigned
by its neighbors to the unnumbered links between the neighbors and by its neighbors to the unnumbered links between the neighbors and
the LSR. The LSR uses this information to find a link with tuple the LSR. The LSR uses this information to find a link with tuple
<Router ID, local identifier> matching the tuple <IP Address, <Router ID, local identifier> matching the tuple <IP Address,
Interface ID> carried in the IF_INDEX TLV. If the matching tuple is Interface ID> carried in the IF_INDEX TLV. If the matching tuple is
found, the match identifies the link for which the LSR has to perform found, the match identifies the link for which the LSR has to perform
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As part of the Explicit Route TLV processing, or to be more precise, As part of the Explicit Route TLV processing, or to be more precise,
as part of the next hop selection, if the outgoing link is as part of the next hop selection, if the outgoing link is
unnumbered, the REQUEST message that the node sends to the next hop unnumbered, the REQUEST message that the node sends to the next hop
MUST include the IF_ID TLV, with the IP address field of that TLV set MUST include the IF_ID TLV, with the IP address field of that TLV set
to the Router ID of the node, and the Interface ID field of that TLV to the Router ID of the node, and the Interface ID field of that TLV
set to the identifier assigned to the link by the node. set to the identifier assigned to the link by the node.
8. IANA Considerations 8. IANA Considerations
RFC3036 [LDP] defines the LDP TLV name space. RFC3212 [CD-LDP] RFC3036 [LDP] defines the LDP TLV name space. RFC3212 [CD-LDP]
further subdivides the range of RFC 3036 from that TLV space for TLVs further subdivides the range of that TLV space for TLVs associated
associated with the CR-LDP in the range 0x0800 - 0x08FF. with the CR-LDP in the range 0x0800 - 0x08FF, and defines the rules
for the assignment of TLVs within that range using the terminology of
Following the policies outlined in [IANA], TLV types in this range BCP 26 "Guidelines for Writing an IANA Considerations Section in
are allocated through an IETF Consensus action. RFCs". Those rules apply to the assignment of TLV Types for the
Unnumbered Interface ID and LSP_TUNNEL_INTERFACE_ID TLVs defined in
This document makes the following assignments: this document.
TLV Type
-------------------------------------- ----------
UNNUMBERED_INTERFACE_ID 0x0805
LSP_TUNNEL_INTERFACE_ID 0x08??
9. Security Considerations 9. Security Considerations
This document extends CR-LDP and raises no new security issues. CR- This document extends CR-LDP and raises no new security issues. CR-
LDP inherits the same security mechanism described in Section 4.0 of LDP inherits the same security mechanism described in Section 4.0 of
[LDP] to protect against the introduction of spoofed TCP segments [LDP] to protect against the introduction of spoofed TCP segments
into LDP session connection streams. into LDP session connection streams.
10. Acknowledgments 10. Acknowledgments
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