UDP Encapsulation for IP Tunneling draft-yong-tsvwg-udp-4-ip-tunneling-01 Lucy Yong, Xiaohu Xu * Here to present March 2013 Orlando FL

Background Existing Tunneling solutions IP Infrastructure Networks carry tunneled traffic Transit nodes are not aware of tunneled traffic/protocols Tunneled traffic may be IP or non-IP packets Some tunneled layer protocols already deployed Network overlay example: IPv6 over IPv4, GRE, etc Network virtualization overlay: MPLS VPN, VXLAN, NVGRE, etc Existing Tunneling solutions IP-in-IP [RFC2003] GRE [RFC2784] L2TPv3 [RFC3931]

Background Cont. IP Networks are built on parallelized capacity e.g. multiple 10G links bundled together as a mx10G link equal cost multiple paths (ECMP) is available to one end operator desire to use all the paths carrying the tunneled traffic w/ the same tunnel end point IP Networks already support ECMP and LAG Hashing based load distribution is the common practice IP header and TCP/UDP header is used for ECMP load distribution i.e. (five tuple) packets with the same five tuple is carried on the same path, which ensures no packet re-ordering UDP src and dst ports are used as entropy in the load distribution The purpose… These are real-world use cases we know of so far. We’re hoping to gather more use cases from the folks present here in order to make this work worthwhile. In this presentation I stay away from mash up examples so we can focus on key enabling properties individually. The presentation is divided into four focus areas … 1-2-3-4 These focus areas are further grouped by NVO properties driven by example use cases which we’ll talk about.

Problem Statement Tunneled traffic may be carried over IP network where ECMP/LAG is required To avoid tunneled flow packets re-ordering, IP network MUST keep a tunneled flow in the same path solution for this is to have an entropy field in packets for IP network with ECMP, in which a tunneled flow packets is assigned to the same entropy value Solution weakness for IP network with ECMP IP-in-IP [RFC2003] does not have a place for entropy info GRE [RFC2784] has an entropy field but requires transit router special processing L2TPv3 [RFC3931] has the same capability and problem as GRE

What is in this draft? Specify a generic UDP encapsulation method for any tunneled layer protocol over IP networks w/ ECMP Achieve it w/o any change in IP network transit nodes the same LB method for both host based apps. and tunneled apps. Have a flow entropy field in UDP header UDP src and dst ports are commonly used as entropy in IP network tunneled packets w/ the same entropy value carried through the same path in IP network may map one or more tunneled flows to the same value Have a way to identify tunneled protocol in the UDP header needed in order to support any tunneled layer protocol Achieve it w/o any change of tunneled layer protocols Specify tunnel endpoint process procedures and error handling

UDP Encapsulation for IP Tunneling UDP source port is used as the flow entropy field may be set to any value by the tunnel ingress Varying the value according to the payload flow will enable load balancing within IP networks UDP destination port is set to indicate the tunneled layer protocol that is registered under IANA Other UDP header fields remain the same as in [RFC768] RECOMMEND that the UDP checksum field is set to zero.

UDP Header Usage in this draft UDP port usage here is different from before Not for demultplexing transport connection at end point Nor identifying an upper layer service Header does not provide transport function for upper layer application UDP ports are to provide flow entropy and the tunneled protocol type UDP ports have been used as entropy in IP network The latter is necessary in order to support any tunneled layer protocol Note: VXLAN have been implemented in this way

Comment from Joe Touch Alternative ways to indicate tunneled layer protocol type A: Use one UDP dst. port to indicate the service for underlying IP network ECMP Use a shim header in the payload to indicate the payload protocol type that are registered under IANA This allows an IP tunnel carrying multiple layer protocols B: Tunnel end point always signals the tunneled protocol type ahead This only applies when each IP tunnel carries one tunneled protocol

Draft Contributors John Drake Adrian Farrel Juniper Networks Carlos Pignataro Cisco System Yiu Lee Comcast Edward Crabbe Google, Inc. Vishwas Manral Hewlett-Packard Corp. Yangbin Fan China Telecom

Next Step Welcome comment and feedback on this Determine the proper way to indicate tunneled protocol Each option has pros and cons Authors prefer the option described in the draft because VXLAN already implements this way Seek WG adoption of this