Extended MPLS/PW PID Mustapha A

1
Extended MPLS/PW PIDMustapha Aïssaoui, Matthew
Bocci, David Watkinson, AlcatelAndrew G.
Malis, Tellabs

• draft-aissaoui-extended-pid-00.txt
• Extends proposed MPLS/PW PID to identify
• Multiple user protocols when multiplexed in a PW
  or MPLS LSP
• multiple control plane protocols carried in a PW
  or MPLS LSP
• Discusses relationship of the control word to the
  MPLS/PW PID

2
MPLS/PW PID for control plane

• MPLS/PW PID is an alternative to special label
  value for MPLS and PW OAM
• allows the use and identification by a PE of
  different control plane protocols, e.g.,
  LSP-Ping/VCCV, Y.1711
• Ensures OAM packets follow same path as
  user-plane packets in the presence of ECMP

3
MPLS/PW PID for User Plane

• Allows interworking of different link layers over
  a MPLS network, where
• each data link layer is terminated locally in a
  PE
• attachment circuits carry multiple user plane
  protocols
• Applications described in
• draft-moreels-multiproto-mpls-01.txt
• draft-sajassi-l2vpn-interworking-01.txt
• MPLS/PW PID is not an alternative to current MPLS
  and PW models
• MPLS LSP and PW carrying single user protocol
  type do not require a MPLS/PW PID

4
Example Application
Transit SP
ISP PoP 1
ISP PoP 2
PE 1
PE 2
FR VC
GigE
One or many PWs

• Payload Types
• IS-IS / CLNP
• IP

• Interworking Options
• Extend FR or Ethernet to remote PE
• Multiple parallel PWs, one for each payload type
• PID translation between FR, PW, and Ethernet

5
Format of MPLS/PW PID

• Same as in draft-allan-mpls-pid-00 except for
• Used a value of 0001 for the first nibble
• Removed the Alert bit
• Format properties
• Compatible with MPLS PID in PWE3 architecture
  (PA0 is a PPP DLL)
• Allows easy translation to/from RFC2427, RFC2684,
  and RFC2878
• Follows user plane protocol representation
  procedures of RFC2427
• Where multiple representations of a protocol
  exist, use of the one with the lowest PA possible
  is required

6
CW and MPLS/PW PID

• MPLS payload identifier (draft-ietf-pwe3-arch-04.t
  xt)
• precedes the PW CW because first nibble following
  the bottom label distinguishes payload from IPv4
  and IPv6
• Drawback both MPLS PID and CW are appended to
  each fragment when fragmentation is applied
• This draft discusses the following alternative
• PW CW to be consistently used for resolving the
  IP aliasing issue
• All PWE3 encapsulation comply except the SONET
  one
• MPLS/PW PID to follow the PW control word
• PW CW is a kind of adaptation layer for the PSN
• MPLS/PW PID appended once in a fragmented packet
• Drawback PID not always in the same position
  since CW is optional
• These are not major issues

7
Conclusions

• Keep current ordering of CW and MPLS/PID unless a
  major issue is raised
• Propose to progress this draft within the
  framework of the PWE3 working group