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This document describes methods for performing lsp-ping traceroute over mpls tunnels and for traceroute of stitched mpls LSPs. The techniques outlined in RFC 4379 are insufficient to perform traceroute FEC validation and path discovery for a LSP that goes over other mpls tunnels or for a stitched LSP. This document describes enhancements to the downstream-mapping TLV (defined in RFC 4379). These enhancements along with other procedures outlined in this document can be used to trace such LSPs.
1.
Introduction
1.1.
Conventions used in this document
2.
Motivation
3.
Packet format
3.1.
Introduction
3.2.
Downstream Detailed Mapping TLV
3.2.1.
Multipath data sub-TLV
3.2.2.
Label stack sub-TLV
3.2.3.
Stack change sub-TLV
3.3.
Deprecation of Downstream Mapping TLV
4.
Performing lsp-ping traceroute on tunnels
4.1.
Transit node procedure
4.1.1.
Addition of a new tunnel
4.1.2.
Transition between tunnels
4.2.
Ingress node procedure
4.2.1.
Processing Downstream Detailed Mapping TLV
4.2.1.1.
Stack Change sub-TLV not present
4.2.1.2.
Stack Change sub-TLV(s) present
4.2.2.
Modifications to handling to EGRESS_OK responses.
4.3.
Handling deprecated Downstream Mapping TLV
5.
Security Considerations
6.
IANA Considerations
7.
Acknowledgements
8.
References
8.1.
Normative References
8.2.
Informative References
§
Authors' Addresses
§
Intellectual Property and Copyright Statements
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This documents describes methods for performing lsp-ping traceroute over mpls tunnels. The techniques outlined in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.) outline a traceroute mechanism that includes FEC validation and ECMP path discovery. Those mechanisms are insufficient and do not provide details in case the FEC being traced traverses one or more mpls tunnels and in case where LSP stitching is in use. This document defines enhancements to the downstream-mapping TLV [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.) to make it more extensible and to enable retrieval of detailed information. Using the enhanced TLV format along with the existing definitions of [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.), this document describes procedures by which a traceroute request can correctly traverse mpls tunnels with proper FEC and label validations.
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The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119] (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.).
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A LSP-Ping traceroute may cross multiple mpls tunnels en-route the destination. Let us consider a simple case.
A B C D E
o -------- o -------- o --------- o --------- o
\_____/ | \______/ \______/ | \______/
LDP | RSVP RSVP | LDP
| |
\____________________/
LDP
| Figure 1: LDP over RSVP tunnel |
When a traceroute is initiated from router A, router B returns downstream mapping information for node C in the echo-response. The next echo request reaches router C with a LDP FEC. Node C is a pure RSVP node and does not run LDP. Node C will receive the packet with 2 labels but only 1 FEC in the Target FEC stack. Consequently, node C will be unable to perform FEC complete validation. It will let the trace continue by just providing next-hop information based on incoming label, and by looking up the forwarding state associated with that label. However, ignoring FEC validation defeats the purpose of control plane validatations. The echo request should contain sufficient information to allow node C to perform FEC validations to catch any misrouted echo-requests.
The above problem can be extended for a generic case of tunnel over tunnel or multiple tunnels (e.g. B-C can be a separate RSVP tunnel and C-D can be a separate RSVP tunnel). The problem of FEC validation for tunnels can be solved if the transit routers (router B in the above example) provide some hint or information to the ingress regarding the start of a new tunnel.
Stitched LSPs involve 2 or more LSP segments stitched together. The LSP segments can be signaled using the same or different signaling protocols. In order to perform an end-to-end trace of a stitched LSP, the ingress needs to know FEC information regarding each of the stitched LSP segments. For example, conside the figure below.
A B C D E F
o -------- o -------- o --------- o -------- o ------- o
\_____/ \______/ \______/ \______/ \_______/
LDP LDP BGP RSVP RSVP
| Figure 2: Stitched LSP |
Consider ingress (A) tracing end-to-end LSP A--F. When an echo request reaches router C, there is a FEC change happening at router C. With current lsp-ping mechanisms, there is no way to convey this information to A. Consequently, when the next echo request reaches router D, router D will know nothing about the LDP FEC that A is trying to trace.
Thus, the procedures outlined [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.) do not make it possible for the ingress node to:
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In many cases there has been a need to associate additional data in the lsping echo response. In most cases, the additional data needs to be associated on a per downstream neighbor basis. Currently, the echo response contains 1 downstream map TLV (DSMAP) per downstream neighbor. But the DSMAP format is not extensible and hence it's not possible to associate more information with a downstream neighbor. This draft defines a new extensible format for the DSMAP and provides mechanisms for solving the tunneled lsp-ping problem using the new format. In summary, the draft makes the following TLV changes:
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A new TLV has been added to the mandatory range of TLVs. The TLV type is pending IANA allocation.
Type # Value Field
------ ------------
TBD Downstream detailed mapping
| Figure 3 |
The Downstream Detailed Mapping object is a TLV that MAY be included in an echo request message. Only one Downstream Detailed Mapping object may appear in an echo request. The presence of a Downstream Mapping object is a request that Downstream Detailed Mapping objects be included in the echo reply. If the replying router is the destination of the FEC, then a Downstream Detailed Mapping TLV SHOULD NOT be included in the echo reply. Otherwise the replying router SHOULD include a Downstream Detailed Mapping object for each interface over which this FEC could be forwarded.
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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MTU | Address Type | DS Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream IP Address (4 or 16 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Interface Address (4 or 16 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-tlv length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. List of Sub TLVs .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Figure 4: Downstream Detailed Mapping TLV |
The Downstream Detailed Mapping TLV format is derived from the Downstream Mapping TLV format. The key change is that variable length and optional fields have been coverted into sub-TLVs. The fields have the same use and meaning as in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.). The newly added sub-TLVs and their fields are as described below.
Sub-tlv length
Total length in bytes of the sub-TLVs associated with this TLV.
Sub-Type Value Field
--------- ------------
TBD Multipath data
TBD Label stack
TBD FEC Stack change
| Figure 5: Downstream Detailed Mapping Sub-TLV List |
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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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Multipath Type | Multipath Length |Reserved (MBZ) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| (Multipath Information) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Figure 6: Multipath Sub-TLV |
The multipath data sub-TLV includes information multipath information. The TLV fields and their usage is as defined in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.).
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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 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Label | Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Downstream Label | Protocol |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Figure 7: Label Stack Sub-TLV |
The Label stack sub-TLV contains the set of labels in the label stack as it would have appeared if this router were forwarding the packet through this interface. Any Implicit Null labels are explicitly included. The number of labels present in the sub-TLV is determined based on the sub-TLV data length. Labels are treated as numbers, i.e., they are right justified in the field. The label format and protocol type are as defined in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.). When the Detailed Downstream Mapping TLV in sent in the echo response, this sub-TLV MUST be included.
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A router SHOULD include the the FEC Stack change sub-TLV when the downstream node in the echo response has a different FEC stack than the FEC stack received in the echo request. One ore more FEC Stack change sub-TLVs MAY be present in the Downstream Detailed Mapping TLV. The format is as below.
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 2 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Operation Type | Address type | FEC-tlv length| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Remote Peer Address (0, 4 or 16 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . FEC TLV . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Figure 8: Stack Change Sub-TLV |
Operation Type
The operation type specifies the action associated with the FEC change. The following operation types are defined.
Type # Operation
------ ---------
1 Push
2 Pop
| Operation Type Values |
A FEC Stack change sub-TLV containing a PUSH operation MUST NOT be followed by a FEC Stack change sub-TLV containing a POP operation. One or more POP operations MAY be followed by one or more PUSH operations. One FEC Stack change sub-TLV MUST be included per FEC change. For example, if 2 labels are going to be pushed, then 1 FEC change sub-TLV MUST be included for each FEC. A FEC Swap operation is to be simulated by including a POP type FEC change sub-TLV followed by a PUSH type FEC change sub-TLV.
A Downstream detailed mapping TLV containing only 1 FEC change sub-TLV with Pop operation is equivalent to EGRESS_OK for the outermost FEC in the FEC stack. The ingress router performing the lsp trace MUST treat such a case as an EGRESS_OK for the outermost FEC.
FEC tlv Length
Length in bytes of the FEC TLV.
Address Type
The Address Type indicates the remote peer's address type. The Address Type is set to one of the following values. The peer address length is determined based on the address type. The address type MAY be different from the address type included in the Downstream Detailed Mapping TLV. This can happen in case the LSP goes over a tunnel of a different address family. The address type MAY be set to Unspecified if the peer-address is either unavailable or the transit router does not wish it provide it for security or administrative reasons.
Type # Address Type Address length
------ ------------ --------------
0 Unspecified 0
1 IPv4 4
2 IPv6 16
| Figure 9: Remote peer address type |
Remote peer address
The remote peer address specifies the remote peer which is the next-hop for the FEC being currently traced. E.g. In the LDP over RSVP case Figure 1 (LDP over RSVP tunnel), router B would respond back with the address of router D as the remote peer address for the LDP FEC being traced. This allows the ingress node to provide helpful information regarding FEC peers. If the operation type is PUSH, the remote peer address is the address of the peer from which the FEC was learned. If the operation type is POP, the remote peer address MAY be set to Unspecified. For upstream assigned labels [I‑D.ietf‑mpls‑upstream‑label] (Aggarwal, R., Rekhter, Y., and E. Rosen, “MPLS Upstream Label Assignment and Context-Specific Label Space,” July 2008.), an operation type of POP will have a remote peer address (the upstream node that assigned the label) and this SHOULD be included in the FEC change sub-TLV.
FEC TLV
The FEC TLV is present only when FEC-tlv length field is non-zero. The FEC TLV specifies the FEC associated with the FEC stack change operation. This TLV MAY be included when the operation type is POP. It SHOULD be included when the operation type is PUSH. The FEC TLV contains exactly 1 FEC from the list of FECs specified in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.). A NIL FEC MAY be associated with a PUSH operation if the responding router wishes to hide the details of the FEC being pushed.
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The Downstream Mapping TLV has been deprecated. LSP-ping procedures should now use the Downstream Detailed Mapping TLV. Detailed procedures regarding interoperability between the deprecated TLV and the new tlv are specified in Section 4.3 (Handling deprecated Downstream Mapping TLV).
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This section describes the procedures to be followed by an ingress node and transit nodes when performing lsp-ping traceroute over mpls tunnels.
| TOC |
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A transit node (Figure 1 (LDP over RSVP tunnel)) knows when the FEC being traced is going to enter a tunnel at that node. Thus, it knows about the new outer FEC. All transit nodes that are the origination point of a new tunnel SHOULD add the a FEC Stack change sub-TLV (Section 3.2.3 (Stack change sub-TLV)) to the Downstream Detailed Mapping TLV (Figure 4 (Downstream Detailed Mapping TLV)) in the echo-response. The transit node SHOULD add 1 FEC Stack change sub-TLV of operation type PUSH, per new tunnel being originated at the transit node.
A transit node that sends a Downstream FEC Stack change sub-TLV in the echo response SHOULD fill the address of the remote peer; which is the peer of the current LSP being traced. If the transit node does not know the address of the remote peer, it MAY leave it as unspecified.
If the transit node wishes to hide the nature of the tunnel from the ingress of the echo-request, then it MAY not want to send details about the new tunnel FEC to the ingress. In such a case, the transit node SHOULD use the NIL FEC. The echo response would then contain a FEC Stack change sub-TLV with operation type PUSH and a NIL FEC. The value of the label in the NIL FEC MUST be set to zero. The remote peer address length MUST be set to 0 and the remote peer address type MUST be set to Unspecified. The transit node SHOULD add 1 FEC Stack change sub-TLV of operation type PUSH, per new tunnel being originated at the transit node.
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A B C D E F
o -------- o -------- o --------- o -------- o ------- o
\_____/ \______/ \______/ \______/ \_______/
LDP LDP BGP RSVP RSVP
| Figure 10: Stitched LSPs |
In the above figure, we have 3 seperate LSP segments stitched at C and D. Node C SHOULD include 2 FEC Stack change sub-TLVs. One with a POP operation for the LDP FEC and one with the PUSH operation for the BGP FEC. Similarly, node D SHOULD include 2 FEC Stack change sub-TLVs, one with a POP operation for the BGP FEC and one with a PUSH operation for the RSVP FEC.
If node C wishes to perform FEC hiding, it SHOULD respond back with 2 FEC Stack change sub-TLVs. One POP followed by 1 PUSH. The POP operation MAY either not include the FEC TLV (by setting FEC TLV length to 0) or set the FEC TLV to contain the LDP FEC. The PUSH operation SHOULD have the FEC TLV contain the NIL FEC.
If node C performs FEC hiding and node D also performs FEC hiding, then node D MAY choose to not send any FEC change sub-TLVs in the echo response since the number of labels has not changed (for the downstream of node D) and the FEC type also has not changed (NIL FEC). If node D performs FEC hiding, then node F will respond as EGRESS_OK for the NIL FEC. The ingress (node A) will know that EGRESS_OK corresponds to the end-to-end LSP.
A B C D E F
o -------- o -------- o --------- o --------- o --------- o
\_____/ | \___________________/ |\_______/
LDP |\ RSVP-A | LDP
| \_______________________________/|
| RSVP-B |
\________________________________/
LDP
| Figure 11: Hierarchical LSPs |
In the above figure, the following sequence of FEC change sub-TLVs will be performed
Node B:
Respond with 2 FEC change sub-TLVs: PUSH RSVP-B, PUSH RSVP-A.
Node D:
Respond with EGRESS_OK when RSVP-A is top of FEC stack. Downstream information for node E when echo request contains RSVP-B as top of FEC stack.
If node B is performing tunnel hiding, then:
Node B:
Respond with 2 FEC change sub-TLVs: PUSH NIL-FEC, PUSH NIL-FEC.
Node D:
Respond with either EGRESS_OK (if D can co-relate that the NIL-FEC corresponds to RSVP-A which is terminating at D) or respond with FEC change sub-TLV: POP (since D knows that number of labels towards next-hop is decreasing).
A B C D E F G
o -------- o -------- o ------ o ------ o ----- o ----- o
LDP LDP BGP \ RSVP RSVP / LDP
\_____________/
LDP
| Figure 12: Stitched hierarchical LSPs |
In the above case, node D will send 3 FEC change sub-TLVs. One POP (for the BGP FEC) followed by 2 PUSHes (one for LDP and one for RSVP).
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It is the responsibility of an ingress node to understand tunnel within tunnel semantics and lsp stitching semantics when performing a lsp traceroute. This section describes the ingress node procedure based on the kind of response an ingress node receives from a transit node.
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Downstream Detailed Mapping TLV should be processed in procedures similar to those of Downstream Mapping TLV, defined in Section 4.4 of [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.)
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This would be the default behavior as described in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.). The ingress node MUST perform echo response processing as per the procedures in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.).
| TOC |
If one or more FEC Stack change sub-TLVs (Section 3.2.3 (Stack change sub-TLV)) are received in the echo response, the ingress node SHOULD process them and perform some validation.
The FEC stack changes are associated with a downstream neighbor and along a particular path of the LSP. Consequently, the ingress will need to maintain a FEC-stack per path being traced (in case of multipath). All changes to the FEC stack resulting from the processing of FEC Stack change sub-TLV(s) should be applied only for the path along a given downstream neighbor. The following algorithm should be followed for processing FEC Stack change sub-TLVs.
push_seen = FALSE
fec_stack_depth = current-depth-of-fec-stack-being-traced
saved_fec_stack = current_fec_stack
while (sub-tlv = get_next_sub_tlv(downstream_detailed_map_tlv))
if (sub-tlv == NULL) break
if (sub-tlv.type == FEC-Stack-Change) {
if (sub-tlv.operation == POP) {
if (push_seen) {
Drop the echo response
current_fec_stack = saved_fec_stack
return
}
if (fec_stack_depth == 0) {
Drop the echo response
current_fec_stack = saved_fec_stack
return
}
Pop FEC from FEC stack being traced
fec_stack_depth--;
}
if (sub-tlv.operation == PUSH) {
push_seen = 1
Push FEC on FEC stack being traced
fec_stack_depth++;
}
}
}
if (fec_stack_depth == 0) {
Drop the echo response
current_fec_stack = saved_fec_stack
return
}
| Figure 13: FEC Stack Change Sub-TLV Processing Guideline |
The next echo request along the same path should use the modified FEC stack obtained after processing the FEC Stack change sub-TLVs. A non-NIL FEC guarantees that the next echo request along the same path will have the Downstream Detailed Mapping TLV validated for IP address, Interface address and label stack mismatches.
If the top of the FEC stack is a NIL FEC and the echo response does not contain any FEC Stack change sub-TLV, then it does not necessarily mean that the LSP has not started traversing a different tunnel. It could be that the LSP associated with the NIL FEC terminated at a transit node and at the same time a new LSP started at the same transit node. The NIL FEC would now be associated with the new LSP (and the ingress has no way of knowing this). Thus, it is not possible to build an accurate hierarchical LSP topology if a traceroute contains NIL FECs.
| TOC |
The procedures above allow the addition of new FECs to the original FEC being traced. Consequently, the EGRESS_OK response from a downstream node may not necessarily be for the FEC being traced. It could be for one of the new FECs that was added. On receipt of an EGRESS_OK response, the ingress should check if the depth of Target FEC sent to the node that just responded, was the same as the depth of the FEC that was being traced. If it was not, then it should pop the an entry from the Target FEC stack and resend the request with the same TTL (as previously sent). The process of popping a FEC is to be repeated until either the ingress receives a non-EGRESS_OK response or until all the additional FECs added to the FEC stack have already been popped. Using EGRESS_OK responses, an ingress can build a map of the hierarchical LSP structure traversed by a given FEC.
| TOC |
The Downstream Mapping TLV has been deprecated. Applications should now use the Downstream Detailed Mapping TLV. The following procedures SHOULD be used for backward compatibility with routers that do not support the Downstream Detailed Mapping TLV.
| TOC |
Tracing inside a tunnel might have some security implications. There are different ways to prevent tracing tunnel details.
In inter-AS (autonomous system) scenarios, information regarding the LSP FEC change(s) SHOULD NOT be passed across domains. A NIL FEC MAY be used to make the trace go through without false positives. An ASBR (autonomous system border router) may choose to intercept all echo requests and echo responses and change them to hide FEC information from other domains. Detailed operation regarding the same is outside the scope of this document. Passing of FEC change information between domains MAY be done if the two AS domains belong to the same provider/organization.
Other security considerations, as discussed in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.) are also applicable to this document.
| TOC |
This document introduces a new Downstream Detailed Mapping TLV. It is requested that IANA assign a TLV type in the range of 0-32767 from the TLV type registry created in [RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.).
It is requested that IANA create a new registry for the Sub-Type field of Downstream Detailed Mapping TLV. The valid range for this is 0-65535. Assignments in the range 0-16383 and 32768-49161 are made via Standards Action as defined in [RFC3692] (Narten, T., “Assigning Experimental and Testing Numbers Considered Useful,” January 2004.); assignments in the range 16384-31743 and 49162-64511 are made via Specification Required ([RFC4379] (Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” February 2006.)); values in the range 31744-32767 and 64512-65535 are for Vendor Private Use, and MUST NOT be allocated. If a sub-TLV has a Type that falls in the range for Vendor Private Use, the Length MUST be at least 4, and the first four octets MUST be that vendor's SMI Enterprise Code, in network octet order. The rest of the Value field is private to the vendor.
It is requested that IANA assign a sub-TLV types from the 0-32767 range for the sub-TLVs defined in Figure 5 (Downstream Detailed Mapping Sub-TLV List).
| TOC |
The authors would like to thank Yakov Rekhter and Adrian Farrel for their suggestions on the draft.
| TOC |
| TOC |
| [RFC2119] | Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” BCP 14, RFC 2119, March 1997 (TXT, HTML, XML). |
| [RFC3692] | Narten, T., “Assigning Experimental and Testing Numbers Considered Useful,” BCP 82, RFC 3692, January 2004 (TXT). |
| [RFC4379] | Kompella, K. and G. Swallow, “Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures,” RFC 4379, February 2006 (TXT). |
| TOC |
| [I-D.ietf-mpls-upstream-label] | Aggarwal, R., Rekhter, Y., and E. Rosen, “MPLS Upstream Label Assignment and Context-Specific Label Space,” draft-ietf-mpls-upstream-label-07 (work in progress), July 2008 (TXT). |
| TOC |
| Nitin Bahadur | |
| Juniper Networks, Inc. | |
| 1194 N. Mathilda Avenue | |
| Sunnyvale, CA 94089 | |
| US | |
| Phone: | +1 408 745 2000 |
| Email: | nitinb@juniper.net |
| URI: | www.juniper.net |
| Kireeti Kompella | |
| Juniper Networks, Inc. | |
| 1194 N. Mathilda Avenue | |
| Sunnyvale, CA 94089 | |
| US | |
| Phone: | +1 408 745 2000 |
| Email: | kireeti@juniper.net |
| URI: | www.juniper.net |
| George Swallow | |
| Cisco Systems | |
| 1414 Massachusetts Ave | |
| Boxborough, MA 01719 | |
| US | |
| Email: | swallow@cisco.com |
| URI: | www.cisco.com |
| TOC |
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