interface (Protocols IS-IS)
Statement introduced before Junos OS Release 7.4.
Statement introduced in Junos OS Release 9.0 for EX Series switches.
Statement introduced in Junos OS Release 12.1 for the QFX Series.
Statement introduced in Junos OS Release 14.1X53-D20 for the OCX Series.
no-eligible-remote-backup option introduced in Junos OS Release 14.2 for the MX Series.
interface-group-holddown-delay option introduced in Junos OS Release 15.2 for the MX Series.
max-hello-size option introduced in Junos OS Release 17.1 for the MX Series.
Configure interface-specific IS-IS properties. To configure more than one interface, include the interface statement multiple times.
Enabling IS-IS on an interface (by including the interface statement at the [edit protocols isis] or the [edit routing-instances routing-instance-name protocols isis] hierarchy level), disabling it (by including the disable statement), and not actually having IS-IS run on an interface (by including the passive statement) are mutually exclusive states.
all—Have Junos OS create IS-IS interfaces automatically. If you include this option, disable IS-IS on the management interface (fxp0).
interface-name—Name of an interface. Specify the full interface name, including the physical and logical address components.
The checksum cannot be enabled with MD5 hello authentication on the same interface.
The csnp-interval statement is effective only when configured on LAN interfaces.
As an OSI Layer 2 protocol, IS-IS does not support data fragmentation. Therefore, maximum packet sizes must be established and supported between two routers. During adjacency establishment, the IS-IS protocol makes sure that the link supports a packet size of 1492 bytes by padding outgoing hello packets up to the maximum packet size of 1492 bytes. This is the default behavior of the Junos OS IS-IS implementation. However, Junos OS provides an option to disable hello padding that can override this behavior.
By default, the time delay for a routing device is 20 seconds.
LDP synchronization is supported only on point-to-point interfaces and LAN interfaces configured as point-to-point interfaces under IS-IS. LDP synchronization is not supported during graceful restart. To advertise the maximum cost metric until LDP is operational for LDP synchronization, include the ldp-synchronization statement.
When an interface has been in the holddown state for more than 3 minutes, a system log message with a warning level is sent. This message appears in both the messages file and the trace file.
To disable the transmission of all link-state PDUs, set the interval to 0. Link-state PDU throttling by use of the lsp-interval statement controls the flooding pace to neighboring routing devices in order to not overload them.
Also, consider that control traffic (such as link-state PDUs and related packets) might delay user traffic (information packets) because control traffic always has precedence in terms of scheduling on the routing device interface cards. Unfortunately, the control traffic transmission rate is not decreased on low-bandwidth interfaces, such as DS-0 or fractional T1 and E1 interface. Line control traffic stays the same. On a low-bandwidth circuit that is transmitting 30 full-MTU-sized packets, there is not much bandwidth left over for other types of packets.
To create a mesh group and designate that an interface be part of the group, assign a mesh-group number to all the routing device interfaces in the group. To prevent an interface in the mesh group from flooding link-state PDUs, configure blocking on that interface.
On QFX10000 switches, we strongly recommend that you configure all IS-IS interfaces, including peer interfaces, as point-to-point interfaces. If you do not, you might experience session flaps, that is, IS-IS sessions that go down and then come back up, when IS-IS is configured in virtual routing and forwarding (VRF) instances. When you scale IS-IS in any scenario, you might also experience scaling issues if you do not configure IS-IS interfaces as point-to-point interfaces.
The remaining statements are explained separately. See CLI Explorer.
Required Privilege Level
routing—To view this statement in the configuration.
routing-control—To add this statement to the configuration.