Configuring Application-Specific Link Attribute on an OSPF Interface
Starting in Junos OS and Junos OS Evolved Release 22.2R1, you can advertise different te-attributes such as te-metric, delay-metric, or admin-groups for RSVP and flexible algorithms on the same link. This is done using flexible algorithm specific application-specific link attribute as defined in RFC 8920.
To configure application-specific link attribute based flexible algorithm on an OSPF Interface:
- Create an OSPF area.
[edit protocols] user@host#set protocols ospf area area-id
For example:
[edit protocols] user@host#set protocols ospf area 0.0.0.0
- Specify the interface.
[edit protocols ospf area 0.0.0.0] user@host#set interface interface-name
For example:
[edit protocols ospf area 0.0.0.0] user@host#set interface ge-0/0/0.0
- Configure application-specific link attribute on the OSPF interface of the
device.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0] user@host#set application-specific
- Specify the attribute group.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific] user@host#set attribute-group name
For example:
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific] user@host#set attribute-group asla
- Configure flexible algorithm specific te-attributes such as te-metric, delay-metric,
and admin-groups. Specify the te-metric for the attribute group. The te-metric indicates
the metric type based on which OSPFv2 calculates the path.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific attribute-group asla] user@host#set te-metric
For example:
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific] user@host#set 15
- Specify the admin-group for the attribute group.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific attribute-group asla] user@host#set admin-group
For example:
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific] user@host#set green
- Specify delay-metric for the attribute group.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific attribute-group asla] user@host#set delay-metric
For example:
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific] user@host#set 123123
- In case delay-metric is not configured, specify advertise-interface-delay to fetch the
delay values from the interface configuration hierarchy, that is legacy delay
values.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific attribute-group asla] user@host#set advertise-interface-delay
For example:
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific] user@host#set 123125
Note:The following configuration can be committed only if all of the following criteria match:
-
An application is associated with the attribute group.
-
Delay-metric is not configured in the hierarchy.
-
Interface level delay configurations are present.
-
- Specify the application for the attribute group. In the current implementation, only
flexible algorithm can be configured as an application. An attribute group can have more
than one applications associated with it and it equates to a single application-specific
link attribute with the application bits set in the standard application identifier bit
mask field of the application-specific link attribute sub.
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific attribute-group asla] user@host#set application aplication-name
[edit protocols ospf area 0.0.0.0 interface ge-0/0/0.0 application-specific attribute-group asla] user@host#set application flex-algorithm
- Enter
commitfrom the configuration mode. - Specify strict-asla-based-flex-algorithm to mandate that flexible algorithm path
computations use only the links which advertise relevant te-attributes through
application-specific link attribute.
[edit protocols ospf source-packet-routing] user@host#set strict-asla-based-flex-algorithm
- Enter
commitfrom the configuration mode.To verify your configuration results, use the
show protocolsoperational command.ospf { area 0.0.0.0 interface ge-0/0/0.0 { application-specific { attribute-group asla { te-metric 15; admin-group green; delay-metric 123123; advertise-interface-delay; application flex-algorithm; } } } source-packet-routing { strict-asla-based-flex-algorithm; } }The Junos OS and Junos OS Evolved implementation supports application-specific link attribute subTLV to comply with RFC 8920. The application-specific link attribute sub-TLV is a sub-TLV of the OSPFv2 extended Link TLV as defined in RFC 7684.
To verify the presence of application-specific link attribute sub-TLVs in the OSPF database use the
show ospf database extensiveoperational command.user@host> show ospf database advertising-router self extensive lsa-id 10.0.0.2
OSPF database, Area 0.0.0.0 Type ID Adv Rtr Seq Age Opt Cksum Len OpaqArea*10.0.0.2 100.100.100.100 0x80000007 665 0x22 0x649d 104 Opaque LSA Extended Link (1), length 80: Link Type (1), length 1: 1 Link Id (2), length 4: 10.1.1.1 Link Data (3), length 4: 10.21.1.1 Adjacency Sid (2), length 7: Flags (1), length 1: 0x60 MT ID (2), length 1: 0 Weight (3), length 1: 0 Label (4), length 3: 17 Application Specific Link Attribute (10), length 52: SABM Length (1), length 1: 4 UDABM Length (2), length 1: 0 SABM (3), length 4: 0x10 UDABM (4), length 0: 0x0 TEMetric (5), length 4: 10 UnidirecLinkDelay (27), length 4: 123 MinMaxUnidirecLinkDelay (28), length 8: Min DM: 123, Max DM: 123 UnidirecLinkDelayVar (29), length 4: 0 Color (9), length 4: 2 Gen timer 00:34:55 Aging timer 00:48:55 Installed 00:11:05 ago, expires in 00:48:55, sent 00:11:05 ago Last changed 00:11:05 ago, Change count: 6, Ours, TE Link ID: 0The output displays application-specific link attribute sub-TLV fields and attributes.