As4 Number Representation - Dell C9000 Series Networking Configuration Manual

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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.

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

Dell(conf-router_bgp)#bgp asnotation asdot

Dell(conf-router_bgp)#show conf

Border Gateway Protocol IPv4 (BGPv4)