Configure 4-byte AS numbers

Configure AS numbers using the 4-byte format and represent the numbers in octets.

Before you begin

You cannot modify the global BGP configuration unless BGP is disabled.
Make sure that you define AS numbers in policies the same way that you configure them for the router. The choices are asplain (regular expression) or asdot (dot notation). If you create policies using asplain and configure the switch with asdot, the match will not occur.

About this task

Use BGP 4–byte AS numbers to ensure the continuity of loop-free inter-domain routing information between autonomous systems and to control the flow of BGP updates as 2 byte AS numbers will deplete soon. AS Plain notation format is the default and the preferred form of representing 4–byte AS numbers over the AS dot notation format.

You have an option to configure AS dot notation format as well. With AS dot notation, analyzing and troubleshooting any issues encountered becomes difficult as it is incompatible with the regular expressions used by most of the network providers.

If you enable 4-byte AS numbers, or the dotted octet notation, for the Global Router (VRF0), the configuration is inherited by user-defined VRFs. You cannot enable 4-byte AS numbers on individual user-defined VRFs.

Procedure

In the navigation pane, expand Configuration > IP.
Select BGP.
Select the Generals tab.
To change the AS number format, select disable for AdminStatus.
Select Apply.
In 4-byteAs , select enable.
In AsDot, select enable.
In LocalAs, type the 4-byte AS number in octets.
In AdminStatus, select enable.
Select Apply.

Generals Field Descriptions

Use the data in the following table to use the Generals tab.


Name	Description
bgpVersion	Specifies the version of BGP that operates on the router. Note: This parameter only applies to VRF 0.
Identifier	Specifies the BGP router ID number.
AdminStatus	Enables or disables BGP on the router. The default is disable. You cannot enable AdminStatus until you change the LocalAS value to a nonzero value.
4ByteAs	Enables or disables 4–byte AS numbers. The default is disable. Note: This parameter only applies to VRF 0.
LocalAs	Configures the local AS number. You cannot change the LocalAs value if AdminStatus is enable. The switch does not support this parameter with BGP +. Note: If the inserted LocalAs is 0, then the LocalAs in that VRFcontext loses its significance and it becomes the LocalAs configured in GlobalRouter (the equivalence to CLI commands ip bgp vrf-as 0 and no ip bgp vrf-as or default ip bgp vrf-as).
AsDot	Enables or disables representing AS numbers in octets. The default is disable so the switch uses the plain notation format The AS dot notation is easier to read and remember than the AS plain notation, but it can be difficult to convert from AS plain to AS dot. The IETF prefers the AS plain notation. The switch does not support this parameter with BGP +. Note: This parameter only applies to VRF 0.
Aggregate	Enables or disables aggregation. The default is enable.
DefaultMetric	Configures the metric sent to BGP neighbors. The default metric determines the cost of a route a neighbor uses. Use this parameter in conjunction with the redistribute parameters so that BGP uses the same metric for all redistributed routes. The default is -1. The range is -1–2147483647.
DefaultLocalPreference	Specifies the default local preference. The local preference indicates the preference that AS border routers assign to a chosen route when they advertise it to iBGP peers. The default is 100. The range is 0–2147483647.
AlwaysCompareMed	Enables or disables the comparison of the multi-exit discriminator (MED) parameter for paths from neighbors in different autonomous systems. The system prefers a path with a lower MED over a path with a higher MED. The default is disable.
DeterministicMed	Enables or disables deterministic MED. Deterministic MED compares the MEDs after routes advertised by different peers in the same AS are chosen. The default is disable.
AutoPeerRestart	Enables or disables the process that automatically restarts a connection to a BGP neighbor. The default is enable.
AutoSummary	Enables or disables automatic summarization. If you enable this varialble, BGP summarizes networks based on class limits (for example, Class A, B, or C networks). The default is enable.
NoMedPathIsWorst	Enables or disables NoMedPathIsWorst. If you enable this variable, BGP treats an update without a MED attribute as the worst path. The default is enabled.
BestPathMedConfed	Enables or disables the comparison of MED attributes within a confederation. The default is disable.
DebugMask	Displays the specified debug information for BGP global configurations. The default value is none. Other options are none disables all debug messages. event enables the display of debug event messages. state enables display of debug state transition messages. update enables display of debug messages related to updates transmission and reception. error enables the display of debug error messages. trace enables the display of debug trace messages. init enables the display of debug initialization messages. all enables all debug messages. packet enables the display of debug packet messages. warning enables the display of debug warning messages. filter enables the display of debug messages related to filtering.
IgnoreIllegalRouterId	Enables BGP to overlook an illegal router ID. For example, this variable enables the acceptance of a connection from a peer that sends an open message using a router ID of 0. The default is enable.
Synchronization	Enables or disables the router to accept routes from BGP peers without waiting for an update from the IGP. The default is enable.
MaxEqualcostRoutes	Configures the maximum number of equal-cost-paths that are available to a BGP router by limiting the number of equal-cost-paths the routing table can store. The default value is 1; the range is 1–8.
IbgpReportImportRoute	Configures BGP to report imported routes to an interior BGP (iBGP) peer. This variable also enables or disables reporting of non-BGP imported routes to other iBGP neighbors. The default is enable.
FlapDampEnable	Enables or disables route suppression for routes that go up and down (flap). The default is disable.
QuickStart	Enables or disables the Quick Start feature, which forces the BGP speaker to begin establishing peers immediately, instead of waiting for the auto-restart timer to expire. The default is disable.
TrapEnable	Enables or disables the BGP traps. The default is disable.
ConfederationASIdentifier	Specifies a BGP confederation identifier in the range of 0–65535. Note: This parameter applies only to VRF 0.
ConfederationPeers	Lists adjoining autonomous systems that are part of the confederation in the format (5500,65535,0,10,...,...).. This value can use 0–255 characters. Note: This parameter applies only to VRF 0.
RouteReflectionEnable	Enables or disables the reflection of routes from iBGP neighbors. The default is enable. Note: This parameter applies only to VRF 0.
RouteReflectorClusterId	Configures a reflector cluster ID IP address. This variable applies only if you enable RouteReflectionEnable, and if multiple route reflectors are in a cluster. Note: This parameter applies only to VRF 0.
ReflectorClientToClientReflection	Enables or disables route reflection between two route reflector clients. This variable applies only if RouteReflectionEnable is enable. The default is enable. Note: This parameter applies only to VRF 0.
RouteRefresh	Enables or disables route refresh. If enabled, a route refresh request received by a BGP speaker causes the speaker to resend all route updates it contains in its database that are eligible for the peer that issues the request. Note: This parameter only applies to VRF 0.