Update on

1
Update on BGP-based Auto-Discovery for
L1VPNsdraft-ietf-l1vpn-bgp-auto-discovery-01.tx
tDon Fedyk dwfedyk_at_nortel.comHamid Ould-Brahim
hbrahim_at_nortel.comYakov Rekhter
yakov_at_juniper.net
2
Changes from 00 Version

• Added section 4 referring to BGP TE-Attribute.
• For example a PE may learn from the remote PEs,
  the switching capability, the maximum LSP
  bandwidth of the remote l1vpn interfaces.
• The auto-discovery role is just to distribute
  that information. It is up to the signaling (on
  CE and/or PE) to use or not the TE information
  related to the CE-PE links.
• Added section 5 on scalability
• Mostly focusing on BGP as an auto-discovery
  mechanism for VPNs.
• Completed section 6 on Security Considerations
• Very preliminary.
• Need more input.
• Added section 7 on IANA considerations.

3
Proposal on the NLRI

• Today PPI is carried within the NLRI.
• Proposal Remove distributing PPI information in
  the discovery process.
• Why?
• Because BGP next hop is already carrying
  information about reaching remote PEs.
• This information is useful only when resolving
  the egress CE-PE link ? useful only when
  signaling reaches the remote PE.
• Advantages?
• PPI becomes local to the PE (A PE needs only to
  advertise its address not the set of ports
  attached to L1VPNs).
• In the case of inter-provider (domain) scenarios,
  one provider will not need export its internal
  Provider port information.

4
Current NLRI
CE
PE
VPN-PPI
CPI
PPI
Customer Realm
Provider Realm
---------------------------------------
Length (1 octet)
---------------------------------------
PPI Length (1 octet)
---------------------------------------
PPI (variable)
---------------------------------------
CPI AFI (2 octets)
---------------------------------------
CPI (length)
---------------------------------------
CPI (variable)
---------------------------------------
5
Implications

• Need to uniquely identify CPI in the
  auto-discovery and signaling mechanisms.
• A proposal is to use a Route Distinguisher and
  build VPN-IPv4 and VPN-IPv6 CPIs.
• The tuple ltRD, VPN-IPv4/6gt need to be carried as
  well in signaling.
• On the NLRI
• Remove the CPI Length and the CPI AFI fields.
• Replace PPI field with RD field.
• On the BGP MP-attribute
• No need for new SAFI for l1vpns, just reuse
  existing layer-3 VPN SAFI information
  (VPN-IPv4/VPN-IPv6).

6
New NLRI Proposal

• ---------------------------------------
• Length (2 octets)
• ---------------------------------------
• RD (8 octets)
• ---------------------------------------
• CPI1 (length 1 octet)
• ---------------------------------------
• CPI1 (variable)
• ---------------------------------------
• CPI2 (length 1 octet)
• ---------------------------------------
• CPI2 (variable)
• ---------------------------------------

The RD assures uniqueness of the NLRI ? Need to
be carried within the signaling as part of
VPN-IPv4/VPN-IPv6 address as well.
7
Next?

• Solicit WG feedback on the new NLRI proposal.