| Network Working Group | X. Xu, Ed. |
| Internet-Draft | Huawei |
| Intended status: Standards Track | B. Decraene, Ed. |
| Expires: May 13, 2016 | Orange |
| R. Raszuk | |
| Mirantis Inc. | |
| U. Chunduri | |
| Ericsson | |
| L. Contreras | |
| Telefonica I+D | |
| L. Jalil | |
| Verizon | |
| November 10, 2015 |
Advertising Tunnelling Capability in IS-IS
draft-xu-isis-encapsulation-cap-06
Some networks use tunnels for a variety of reasons. A large variety of tunnel types are defined and the ingress needs to select a type of tunnel which is supported by the egress. This document defines how to advertise egress tunnel capabilities in IS-IS Router Capability TLV.
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This Internet-Draft will expire on May 13, 2016.
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
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Some networks use tunnels for a variety of reasons, such as:
The ingress needs to select a type of tunnel which is supported by the egress. This document describes how to use IS-IS Router Capability TLV to advertise the egress tunnelling capabilities of nodes.
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 RFC 2119 [RFC2119].
This memo makes use of the terms defined in [RFC4971].
Routers advertises their supported encapsulation type(s) by advertising a new sub-TLV of the IS-IS Router CAPABILITY TLV [RFC4971], referred to as Encapsulation Capability sub-TLV. This sub-TLV SHOULD NOT appear more than once within a given IS-IS Router CAPABILITY TLV. The scope of the advertisement depends on the application but it is recommended that it SHOULD be domain-wide. The Type code of the Encapsulation Capability sub-TLV is TBD1, the Length value is variable, and the Value field contains one or more Tunnel Encapsulation Type sub-TLVs. Each Encapsulation Type sub-TLVs indicates a particular encapsulation format that the advertising router supports.
The Tunnel Encapsulation Type sub-TLV is structured as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Tunnel Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Value |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* Tunnel Type (1 octets): identifies the type of tunneling technology being signaled. This document defines the following types:
Unknown types are to be ignored and skipped upon receipt.
* Length (1 octets): unsigned integer indicating the total number of octets of the value field.
* Value (variable): zero or more Tunnel Encapsulation Attribute sub-TLVs as defined in Section 5.
The Tunnel Encapsulation Attribute sub-TLV is structured as follows:
+-----------------------------------+
| Sub-TLV Type (1 Octet) |
+-----------------------------------+
| Sub-TLV Length (1 Octet) |
+-----------------------------------+
| Sub-TLV Value (Variable) |
| |
+-----------------------------------+
* Sub-TLV Type (1 octet): each sub-TLV type defines a certain property about the tunnel Encapsulation sub-TLV that contains this sub-TLV. The following are the types defined in this document:
* Sub-TLV Length (1 octet): unsigned integer indicating the total number of octets of the sub-TLV value field.
* Sub-TLV Value (variable): encodings of the value field depend on the sub-TLV type as enumerated above. The following sub-sections define the encoding in detail.
Any unknown sub-TLVs MUST be ignored and skipped. However, if the Encapsulation Type sub-TLV is understood, the entire sub-TLV MUST NOT be ignored just because it contains an unknown sub-TLV.
If a sub-TLV is erroneous, this specific Tunnel Encapsulation MUST be ignored and skipped. However, others Tunnel Encapsulations MUST be considered.
This sub-TLV has its format defined in [RFC5512] under the name Encapsulation sub-TLV.
This sub-TLV has its format defined in [RFC5512] under the name Protocol Type.
The value field carries the Network Address to be used as tunnel destination address.
If length is 4, the Address Family (AFI) is IPv4.
If length is 16, the Address Family (AFI) is IPv6.
The valued field is a 4 octets opaque unsigned integer.
The color value is user defined and configured locally on the routers. It may be used by the service providers to define policies.
This document requests IANA to allocate a new code point from registry IS-IS Router CAPABILITY TLV.
Value TLV Name Reference ----- ------------------------------------ ------------- TBD1 Tunnel Capabilities This document
This document requests IANA to create a new registry "IGP Tunnel Encapsulation Types" with the following registration procedure:
Registry Name: IGP Tunnel Encapsulation Type.
Value Name Reference
------- ------------------------------------------- -------------
0 Reserved This document
1 L2TPv3 over IP This document
2 GRE This document
3 Transmit tunnel endpoint This document
4 IPsec in Tunnel-mode This document
5 IP in IP tunnel with IPsec Transport Mode This document
6 MPLS-in-IP tunnel with IPsec Transport Mode This document
7 IP in IP This document
8 VXLAN This document
9 NVGRE This document
10 MPLS This document
11 MPLS-in-GRE This document
12 VXLAN-GPE This document
13 MPLS-in-UDP This document
14 MPLS-in-UDP-with-DTLS This document
15 MPLS-in-L2TPv3 This document
16 GTP This document
17-250 Unassigned
251-254 Experimental This document
255 Reserved This document
Assignments of Encapsulation Types are via Standards Action [RFC5226].
This document requests IANA to create a new registry "IGP Tunnel Encapsulation Attribute Types" with the following registration procedure:
Registry Name: IGP Tunnel Encapsulation Attribute Types.
Value Name Reference
------- ------------------------------------ -------------
0 Reserved This document
1 Encapsulation parameters This document
2 Protocol This document
3 End Point This document
4 Color This document
5-250 Unassigned
251-254 Experimental This document
255 Reserved This document
Assignments of Encapsulation Types are via Standards Action [RFC5226].
Security considerations applicable to softwires can be found in the mesh framework [RFC5565]. In general, security issues of the tunnel protocols signaled through this IGP capability extension are inherited.
If a third party is able to modify any of the information that is used to form encapsulation headers, to choose a tunnel type, or to choose a particular tunnel for a particular payload type, user data packets may end up getting misrouted, misdelivered, and/or dropped.
Security considerations for the base OSPF protocol are covered in [RFC1195].
This document is partially inspired by [RFC5512].
The authors would like to thank Carlos Pignataro and Karsten Thomann for their valuable comments on this draft.