Route Distinguishers; Route Reflector; Figure 128: Route Distinguisher - Alcatel-Lucent 7750 SR Manual

VPRN Service Overview

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.
The three Type values are:
•
•
•

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.
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Type Field
(2-bytes)

Figure 128: Route Distinguisher

Type 0: Value Field — Administrator subfield (2 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)
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)
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.
Value Field
(6-bytes)
Assigned number subfield (4 bytes)
Assigned number subfield (2 bytes)
Assigned number subfield (2 bytes)
7750 SR OS Services Guide