Traditional
DOT Format
Format
65001
0.65501
65536
1.0
100000
1.34464
4294967295
65535.65535
When creating Confederations, all the routers in a Confederation must be either 4-Byte or 2-Byte identified
routers. You cannot mix them.
Configure 4-byte AS numbers with the four-octet-support command.
AS4 Number Representation
Multiple representations of 4-byte AS numbers (asplain, asdot+, and asdot) are supported.
NOTE:
The ASDOT and ASDOT+ representations are supported only with the 4-Byte AS numbers feature.
If 4-Byte AS numbers are not implemented, only ASPLAIN representation is supported.
ASPLAIN is the default method the system uses. With the ASPLAIN notation, a 32-bit binary AS number is
translated into a decimal value.
•
All AS numbers between 0 and 65535 are represented as a decimal number when entered in the CLI and
when displayed in the show commands output.
•
AS numbers larger than 65535 are represented using ASPLAIN notation. When entered in the CLI and
when displayed in the show commands output, 65546 is represented as 65546.
ASDOT+ representation splits the full binary 4-byte AS number into two words of 16 bits separated by a
decimal point (.): <high-order 16 bit value>.<low-order 16 bit value>. Some examples are shown in the
following table.
•
All AS numbers between 0 and 65535 are represented as a decimal number, when entered in the CLI
and when displayed in the show commands outputs.
•
AS Numbers larger than 65535 is represented using ASDOT notation as <higher 2 bytes in
decimal>.<lower 2 bytes in decimal>. For example: AS 65546 is represented as 1.10.
ASDOT representation combines the ASPLAIN and ASDOT+ representations. AS numbers less than 65536
appear in integer format (asplain); AS numbers equal to or greater than 65536 appear in the decimal format
(asdot+). For example, the AS number 65526 appears as 65526 and the AS number 65546 appears as 1.10.
Dynamic AS Number Notation Application
A change in the ASN notation type is dynamically applied to the running-config statements.
When you apply or change an ASN notation, the type selected is reflected immediately in the running-
configuration and the show commands (refer to the following two examples).
Example of Dynamic Changes in the Running Configuration When Using the bgp asnotation Command
ASDOT
Dell(conf-router_bgp)#bgp asnotation asdot
Dell(conf-router_bgp)#show conf
!
Border Gateway Protocol IPv4 (BGPv4)
204