Ignore Router-Id For Some Best-Path Calculations; Four-Byte As Numbers - Dell Z9000 Configuration Manual

• If BGP peer outbound route-map has metric configured, all other metrics are overwritten by this
configuration.
NOTE: When redistributing static, connected, or OSPF routes, there is no metric option. Simply
assign the appropriate route-map to the redistributed route.
The following table lists some examples of these rules.
Table 8. Redistributed Route Rules
Command Settings
redistribute isis (IGP cost
= 20)
redistribute isis route-
map set metric 50
redistribute isis metric
100

Ignore Router-ID for Some Best-Path Calculations

Dell Networking OS allows you to 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 Numbers

Dell Networking OS supports 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 and received this capability from another speaker, all the messages will be 4-octet.
The behavior of a 4-Byte BGP speaker is different with the peer 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 is greater than 65535, the dot format is shown when using the show ip
bgp commands. For example, an ASN entered as 3183856184 appears in the show commands as
48581.51768; an ASN of 65123 is shown as 65123. To calculate the comparable dot format for an ASN
from a traditional format, use ASN/65536. ASN%65536.
Traditional Format DOT 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.
178
BGP Local Routing
Information Base
MED: IGP cost 20
MED: IGP cost 50
MED: IGP cost 100
MED Advertised to Peer
WITH route-map
metric-type internal
MED = 20
MED: 50 MED: 50
MED: 100
Border Gateway Protocol IPv4 (BGPv4)
MED Advertised to Peer
WITHOUT route-map
metric-type internal
MED = 0
MED: 50 MED: 50
MED: 100