VPRN Service Overview
Page 1054 7750 SR OS Services Guide
Route Distinguishers
The route distinguisher (RD) is an 8-byte value consisting of 2 major fields, the Type field and
value field. The type field determines how the value field should be interpreted. The 7750 SR OS
implementation supports the three (3) type values as defined in the internet draft.
Figure 128: Route Distinguisher
The three Type values are:
• Type 0: Value Field — Administrator subfield (2 bytes)
Assigned number subfield (4 bytes)
The administrator field must contain an AS number (using private AS numbers is
discouraged). The Assigned field contains a number assigned by the service provider.
• Type 1: Value Field — Administrator subfield (4 bytes)
Assigned number subfield (2 bytes)
The administrator field must contain an IP address (using private IP address space is
discouraged). The Assigned field contains a number assigned by the service provider.
• Type 2: Value Field — Administrator subfield (4 bytes)
Assigned number subfield (2 bytes)
The administrator field must contain a 4-byte AS number (using private AS numbers is
discouraged). The Assigned field contains a number assigned by the service provider.
Route Reflector
Per RFC2547bis the use of Route Reflectors is supported in the service provider core. The support
uses multiple sets of route reflectors for different types of BGP data, including IPv4 and VPN-
IPv4 as well as multicast and IPv6.
Type Field
(2-bytes)
Value Field
(6-bytes)