Ignore Router-ID in Best-Path CalculationYou can avoid unnecessary BGP best-path transitions between external paths under certain conditions. The bgp bestpath router-id ignore command reduces network disruption caused by routing and forwarding plane changes and allows for faster convergence.Four-Byte AS NumbersYou can use the 4-Byte (32-bit) format when configuring autonomous system numbers (ASNs).The 4-Byte support is advertised as a new BGP capability (4-BYTE-AS) in the OPEN message. If a 4-Byte BGP speaker has sent andreceived this capability from another speaker, all the messages will be 4-octet. The behavior of a 4-Byte BGP speaker is different with thepeer depending on whether the peer is a 4-Byte or 2-Byte BGP speaker.Where the 2-Byte format is 1-65535, the 4-Byte format is 1-4294967295. Enter AS numbers using the traditional format. If the ASN isgreater than 65535, the dot format is shown when using the show ip bgp commands. For example, an ASN entered as 3183856184appears in the show commands as 48581.51768; an ASN of 65123 is shown as 65123. To calculate the comparable dot format for an ASNfrom a traditional format, use ASN/65536. ASN%65536.TraditionalFormatDOT Format65001 0.6550165536 1.0100000 1.344644294967295 65535.65535When 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 RepresentationDell Networking OS supports multiple representations of 4-byte AS numbers: asplain, asdot+, and asdot.NOTE: The ASDOT and ASDOT+ representations are supported only with the 4-Byte AS numbers feature. If 4-Byte AS numbersare 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 showcommands output.• AS numbers larger than 65535 are represented using ASPLAIN notation. When entered in the CLI and when displayed in the showcommands 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 (.): 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 showcommands outputs.• AS Numbers larger than 65535 is represented using ASDOT notation as .. Forexample: AS 65546 is represented as 1.10.174 Border Gateway Protocol IPv4 (BGPv4)
