MPLS-TP Loopback Draftdraft-boutros-mpls-tp-loopback-02.txt

Sami Boutros and a

Cast of Thousands

Background

• This draft specifies how to put a bi-directional MPLS LSP into and out-of loopback mode.

• This draft specifies two forms of the mode– Intrusive: loop all traffic (including data)or – Non-instrusive only OAM messages, not

data traffic

Problem Definition

LSR-1 LSR-2 LSR-3

MPLS Bidirectional LSP

MEP1 MIP2 MEP3

• Operator at MEP1 needs to– Set a loopback at a chosen MIP or MEP to– Loop all traffic– Loop only specific OAM traffic

• In the case of full loopback, a capability is needed to first take the LSP out of service

Proposed Solution: LSP into Intrusive Loopback Mode

LSR-1 LSR-2 LSR-3

MPLS Bidirectional LSP

LSR-1 sends a Lock Request to LSR-3to take the MPLS LSP out of service

LSR-3 takes the MPLS-LSP out of service from dataplane and sends an Ack back to LSR-1

LSR-2 setup dataplane to loopback traffic received on this LSP from LSR-1 and sends an ack back to LSR-1

LSR-1 sends a Loopback Request to LSR-2To put the MPLS LSP in Full Loopback mode

Proposed Solution: Intrusive Loopback Mode, flow of data packets

LSR-1 LSR-2 LSR-3

MPLS Bidirectional LSP

LSR-1 sends data packets on the MPLSBidirectional LSP to test connectivity up to LSR2, Packets may contain a sequence #’s.

LSR-2 Loops back the packets sent to LSR-1 LSR-1 could check sequence #’s on packet receivedto guarantee no losses

Putting MPLS-TP in Loopback using NMS

An operator should be able to provision any given LSR to:

1. Lock/Unlock any MPLS-TP LSP.2. Setup any MPLS-TP LSP in loopback mode (either FLB

or OLB).3. Send MPLS OAM packets from a MEP and notify NMS

when MPLS OAM response arrives.

When NMS is used to provision any of the above thefunctionality, the corresponding MPLS OAM message isnot used.

Proposed Solution MPLS OAM Message extensions

The proposed mechanism is based on two messages and A few TLVs which can be transported using one of the

following methods:

– in-band MPLS OAM messages which are forwarded as MPLS packets (non-IP based).

– LSP-Ping messages where IP/UDP packets are used (IP-based) in compliance with RFC 4379.

Changes from -02

• Reorganized TLVs into– two messages– some operation codes – very few TLVs

Message Format 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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Version | Message Type | Operation | Reserved |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Return Code | Cause Code | Message Length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Sender's Handle |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Message ID |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| TLV's |~ ~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

To be added

• Details of using LSP Ping

Issues

• How does this fit with the overall OAM tool set? – E.g. is an independent OAM loopback required

or is it just duplicative of CV ping function?

• What should be the complete OAM organization of ACH code points, message types, function codes– E.g. lock is necessary for full loopback, but

needed for other functions as well

Recommendation

• This draft, along with other OAM drafts, BFD and MPLS Ping be input to MEAD team effort to organized a complete OAM tool set