Title: MPLS over L2TPv3 Encapsulation
1MPLS over L2TPv3 Encapsulation
2L2TPv3 Multiservice Tunneling
Frame Relay
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Version Version Version Version IHL IHL IHL IHL TOS TOS TOS TOS TOS TOS TOS TOS Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length
Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Flags Flags Flags Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset
TTL TTL TTL TTL TTL TTL TTL TTL Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum
Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router)
Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router)
PPP
HDLC
Session ID (32 bits)
Ethernet (VPWS or VPLS)
Cookie (32 or 64 bits, Optional)
Payload
ATM (Cell or Packet)
TDM
- L2TPv3 Encapsulation defined in RFC 3931
(draft-ietf-l2tpext-l2tp-base-14.txt) - MPLS over L2TPv3 encapsulation defined in
draft-townsley-l2tpv3-mpls-02.txt
MPLS
3L2TPv3 Encapsulation
Session ID (32 bits)
Cookie (32 or 64 bits, Optional)
- Session ID and Cookie (if present) may be
signaled, or manually configured. - Session ID is used during decapsulation to
identify service or session context for L2TPv3. - Before processing the L2TPv3 payload, the Cookie
returned via the Session ID context lookup and
the Cookie in the received packet header are
compared to ensure they match.
4MPLS over L2TPv3
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Version Version Version Version IHL IHL IHL IHL TOS TOS TOS TOS TOS TOS TOS TOS Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length Total length
Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Identification Flags Flags Flags Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset Fragment offset
TTL TTL TTL TTL TTL TTL TTL TTL Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Protocol 0x73 (L2TP) Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum Header checksum
Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router) Source IP address (Local address on PE router)
Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router) Destination IP address (Local address on PE router)
Tunnel IP
Session ID (32 bits)
L2TPv3
Cookie (32 or 64 bits, Optional)
Label Exp S TTL
MPLS PDU
MPLS Stack PDU
5Alignment with other MPLS tunneling methods
- Draft-ietf-mpls-in-gre-or-ip-08.txt defines
- MPLS over IP
- MPLS over GRE with full header
- MPLS over GRE with simplified header
- MPLS over IP with IPsec transport mode
- MPLS over GRE with IPsec transport mode
- There are a number of common issues when
encapsulating MPLS over IP, GRE or L2TPv3 which
should continue to be defined in a single
location.
6MPLS over L2TPv3 Specification
- Any specification defining the MPLS over L2TPv3
encapsulation should include an applicability
section similar to that for MPLS over IP vs. MPLS
over GRE vs. MPLS over IPsec. For example, - Two routers may already be adjacent over an
L2TPv3 tunnel for other services outside of
MPLS-based services - Implementation considerations may dictate the use
of MPLS over L2TPv3. For example, a hardware
device might be better equipped to handle L2TPv3,
utilize the L2TPv3 Session ID to aid in
distributed processing of different services,
etc. - L2TPv3 Cookie allows a decapsulating PE to
perform a context lookup validation based on the
L2TPv3 session or service
7Next Steps?
- Add L2TPv3 to the list of methods for tunneling
MPLS traffic - Create a short and concise (5 pages or less!)
MPLS over L2TPv3 WG draft with an appropriate
applicability statement and reference to
draft-ietf-mpls-in-gre-or-ip-08.txt for common IP
encapsulation issues - draft-townsley-l2tpv3-mpls-02.txt could be a
start.
8End.