Internet DRAFT - draft-smith-lisp-layer2
draft-smith-lisp-layer2
Network Working Group M. Smith
Internet-Draft Insieme Networks
Intended status: Experimental D. Dutt
Expires: March 10, 2014 Cumulus Networks
D. Farinacci
lispers.net
F. Maino
Cisco Systems
September 06, 2013
Layer 2 (L2) LISP Encapsulation Format
draft-smith-lisp-layer2-03
Abstract
This memo describes an encapsulation method for carrying Ethernet and
IEEE 802 media access control (MAC) frames within the Locator/ID
Separation Protocol (LISP).
Requirements Language
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].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 10, 2014.
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Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Basic Overview . . . . . . . . . . . . . . . . . . . . . . . 2
3. Layer 2 LISP Encapsulation . . . . . . . . . . . . . . . . . 3
3.1. VXLAN . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. L2 LISP . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. MTU Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Overlays for Network Virtualization . . . . . . . . . . . . . 5
6. LISP Mapping System . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 7
10.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
LISP [RFC6830] specifies an architecture and method for separating
the location of an endpoint from its network identifier. It does
this by using two separate name spaces: EIDs representing the network
identifier of the endpoint and RLOCs representing the network
location of the endpoint. This document extends the LISP
specifications to allow Ethernet/IEEE 802 MAC frames to be carried
within the LISP frame. The MAC addresses of the encapsulated
Ethernet/IEEE 802 MAC frames will be used as EIDs.
2. Basic Overview
L2 LISP specifies the mechanism on which to carry L2 traffic over a
LISP network. Within an L2 LISP environment, the source and
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destination MAC addresses of the Ethernet/IEEE 802.3 packet are used
as the source and destination EIDs. The RLOCs can use IPv4 or IPv6
addressing. The entire MAC frame is encapsulated with the exception
of the preamble and trailing FCS. It should be noted that L2 LISP
introduces the possibility of packet reordering during route topology
changes due to the usage of IP as the network substrate.
This memo addresses the data plane and frame format details of L2
LISP. The control plane details are outside the scope of this memo.
3. Layer 2 LISP Encapsulation
The layer 2 LISP encapsulation is based on the LISP header defined in
the LISP specification [RFC6830]. The UDP and LISP headers are shown
below for reference. For header fields description see section 5.3
of [RFC6830].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 or IPv6 Header (with RLOC addresses) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 4341 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flags| Nonce/Map-Version |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator Status Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
When the headers are used for encapsulating L2 frames, the UDP
Destination Port is set to 8472.
3.1. VXLAN
The VXLAN [I-D.mahalingam-dutt-dcops-vxlan] header is achieved by
setting the L2 LISP header bits as shown in the figure below.
According to [I-D.mahalingam-dutt-dcops-vxlan] the I flag MUST be set
to 1 for a valid VXLAN Network ID (VNI). The figure shows the whole
VXLAN frame, including the original inner L2 frame.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 or IPv6 Header (with RLOC addresses) |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 8472 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |0 0 0 0|I|0 0 0| Not Used |
I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID | Not Used |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Inner Destination MAC Address |
I +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n | Inner Destination MAC Address | Inner Source MAC Address |
n +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
e | Inner Source MAC Address |
r +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opt. Eth.type = C-Tag [802.1Q]| Inner.VLAN Tag Information |
L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2 | Ethertype of Original Payload | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
F | |
r | |
a | Original Ethernet Payload |
m | |
e | |
\ | (Note that the original Ethernet Frame's FCS is not included) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCS (Frame Check Sequence) for Outer Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
3.2. L2 LISP
An L2 LISP frame may optionally use the entire set of fields in the
LISP header to support all of the features of the LISP protocol.
The figure below shows the whole L2 LISP frame, including the
original inner L2 frame.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 or IPv6 Header (with RLOC addresses) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Source Port = xxxx | Dest Port = 8472 |
UDP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ | UDP Length | UDP Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L |N|L|E|V|I|flags| Nonce/Map-Version |
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I \ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
S / | Instance ID/Locator Status Bits |
P +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ | Inner Destination MAC Address |
I +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
n | Inner Destination MAC Address | Inner Source MAC Address |
n +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
e | Inner Source MAC Address |
r +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opt. Eth.type = C-Tag [802.1Q]| Inner.VLAN Tag Information |
L +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
2 | Ethertype of Original Payload | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
F | |
r | |
a | Original Ethernet Payload |
m | |
e | |
\ | (Note that the original Ethernet Frame's FCS is not included) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FCS (Frame Check Sequence) for Outer Ethernet Frame |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4. MTU Considerations
Since additional tunnel headers are prepended, the packet becomes
larger and can exceed the MTU of any link traversed from the ITR to
the ETR. [RFC6830] recommends in IPv4 that packets do not get
fragmented as they are encapsulated by the ITR. Instead, the packet
is dropped and an ICMP Too Big message is returned to the source.
Section 5.4 of [RFC6830] recommends procedure to mitigate MTU issues
for IPv4 or IPv6 packets.
5. Overlays for Network Virtualization
A notable use case for layer 2 LISP encapsulation is the use as an
overlay-based network virtualization architecture to support multi-
tenancy in large data center networks, as stated in
[I-D.ietf-nvo3-overlay-problem-statement]. In this use case, the
24-bit Instance ID serves as virtual network instance ID (VNID) that
is typically used to identify the tenants in large multi-tenant data
centers.
Packet replication in the underlay network to support broadcast,
unknown unicast and multicast overlay services can be done by:
o Ingress replication
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o Use of underlay multicast trees
[RFC6831] and [I-D.farinacci-lisp-mr-signaling] specify how to map a
multicast flow in the EID space during distribution tree setup and
packet delivery in the underlay network.
6. LISP Mapping System
When the LISP mapping database system is used with L2 LISP, it must
support the LISP Canonical Address Format (LCAF) specified in
[I-D.ietf-lisp-lcaf]. More specifically the mapping database system
must support the use of MAC Addresses as LISP EIDs, and the use of
Instance IDs as part of the lookup key.
According to [I-D.ietf-lisp-lcaf] the encoding format for the 2-tuple
<Instance-ID, MAC-address> is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI = 16387 | Rsvd1 | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 2 | IID mask-len | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Instance ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI = 6 | Layer-2 MAC Address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Layer-2 MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
In the case of a single instance of mapping database, no Instance ID
is necessary, and the encoding format for the MAC address is shown
below. In this case an Ethernet IEEE 802.1Q VLAN tag may be part of
the lookup key (encoded in an Instance ID field).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AFI = 6 | Layer-2 MAC Address ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Layer-2 MAC Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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A mapping database system that supports both the LISP Canonical
Address Format, and Instance ID is the LISP Delegated Database Tree
[I-D.ietf-lisp-ddt].
7. Security Considerations
Security in a network carrying L2 LISP should be similar to security
in a normal IPv4 network. Packet filtering on the L2 LISP inner
frames will require that a firewall look inside the L2 LISP packet or
that filtering is done at the ITR/ETR.
8. IANA Considerations
The IANA registry has allocated UDP port number 8472 for the L2 LISP
data packets.
9. Acknowledgements
The authors would like to thank Sumeet Singh, and Ajit Sanzgiri for
their technical and editorial commentary.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
Locator/ID Separation Protocol (LISP)", RFC 6830, January
2013.
[RFC6831] Farinacci, D., Meyer, D., Zwiebel, J., and S. Venaas, "The
Locator/ID Separation Protocol (LISP) for Multicast
Environments", RFC 6831, January 2013.
10.2. Informative References
[I-D.farinacci-lisp-mr-signaling]
Farinacci, D. and M. Napierala, "LISP Control-Plane
Multicast Signaling", draft-farinacci-lisp-mr-signaling-02
(work in progress), July 2013.
[I-D.ietf-lisp-ddt]
Fuller, V., Lewis, D., Ermagan, V., and A. Jain, "LISP
Delegated Database Tree", draft-ietf-lisp-ddt-01 (work in
progress), March 2013.
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[I-D.ietf-lisp-lcaf]
Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical
Address Format (LCAF)", draft-ietf-lisp-lcaf-02 (work in
progress), March 2013.
[I-D.ietf-nvo3-overlay-problem-statement]
Narten, T., Gray, E., Black, D., Fang, L., Kreeger, L.,
and M. Napierala, "Problem Statement: Overlays for Network
Virtualization", draft-ietf-nvo3-overlay-problem-
statement-04 (work in progress), July 2013.
[I-D.mahalingam-dutt-dcops-vxlan]
Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "VXLAN: A
Framework for Overlaying Virtualized Layer 2 Networks over
Layer 3 Networks", draft-mahalingam-dutt-dcops-vxlan-04
(work in progress), May 2013.
Authors' Addresses
Michael Smith
Insieme Networks
California
USA
Email: michsmit@insiemenetworks.com
Dinesh Dutt
Cumulus Networks
California
USA
Email: ddutt@cumulusnetworks.com
Dino Farinacci
lispers.net
California
USA
Email: farinacci@gmail.com
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Fabio Maino
Cisco Systems
California
USA
Email: fmaino@cisco.com
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