Example: Configuring the Accumulated IGP Attribute for BGP
Understanding the Accumulated IGP Attribute for BGP
The interior gateway protocols (IGPs) are designed to handle routing within a single domain or an autonomous system (AS). Each link is assigned a particular value called a metric. The distance between the two nodes is calculated as a sum of all the metric values of links along the path. The IGP selects the shortest path between two nodes based on distance.
BGP is designed to provide routing over a large number of independent ASs with limited or no coordination among respective administrations. BGP does not use metrics in the path selection decisions.
The accumulated IGP (AIGP) metric attribute for BGP enables deployment in which a single administration can run several contiguous BGP ASs. Such deployments allow BGP to make routing decisions based on the IGP metric. In such networks, it is possible for BGP to select paths based on metrics as is done by IGPs. In this case, BGP chooses the shortest path between two nodes, even though the nodes might be in two different ASs.
The AIGP attribute is particularly useful in networks that use tunneling to deliver a packet to its BGP next hop. The Juniper Networks® Junos® operating system (Junos OS) currently supports the AIGP attribute for two BGP address families, family inet labeled-unicast and family inet6 labeled-unicast.
AIGP impacts the BGP best-route decision process. The AIGP attribute preference rule is applied after the local-preference rule. The AIGP distance is compared to break a tie. The BGP best-route decision process also impacts the way the interior cost rule is applied if the resolving next hop has an AIGP attribute. Without AIGP enabled, the interior cost of a route is based on the calculation of the metric to the next hop for the route. With AIGP enabled, the resolving AIGP distance is added to the interior cost.
Starting in Release 20.2R1, Junos OS supports the translation of AIGP metric to MED. You can enable this feature when you want the MED to carry the end to end AIGP metric value, which is used to choose the best path. This is especially useful in Inter-AS MPLS VPNs solution, where customer sites are connected via two different service providers, and customer edge routers want to take IGP metric based decision. You can configure a minimum-aigp to prevent unnecessary update of route when effective-aigp changes past the previously known lowest value. Effective AIGP is the AIGP value advertised with the route plus the IGP cost to reach the nexthop. You can configure effective-aigp and minimum-effective-aigp statements at the [edit protocols bgp group <group-name> metric-out] and [edit policy-options policy-statement <name> then metric] hierarchy levels.
The AIGP attribute is an optional non-transitive BGP path attribute and has been standardized with the RFC7311, The Accumulated IGP Metric Attribute for BGP.
See also
Example: Configuring the Accumulated IGP Attribute for BGP
This example shows how to configure the accumulated IGP (AIGP) metric attribute for BGP.
Requirements
This example uses the following hardware and software components:
Seven BGP-speaking devices.
Junos OS Release 12.1 or later.
Overview
The AIGP attribute enables deployments in which a single administration can run several contiguous BGP autonomous systems (ASs). Such deployments allow BGP to make routing decisions based on the IGP metric. With AIGP enabled, BGP can select paths based on IGP metrics. This enables BGP to choose the shortest path between two nodes, even though the nodes might be in different ASs. The AIGP attribute is particularly useful in networks that use tunneling to deliver a packet to its BGP next hop. This example shows AIGP configured with MPLS label-switched paths.
To enable AIGP, you include the aigp statement in the BGP configuration on a protocol family basis. Configuring AIGP on a particular family enables sending and receiving of the AIGP attribute on that family. By default, AIGP is disabled. An AIGP-disabled neighbor does not send an AIGP attribute and silently discards a received AIGP attribute.
Junos OS supports AIGP for family inet labeled-unicast and family inet6 labeled-unicast. The aigp statement can be configured for a given family at the global BGP, group, or neighbor level.
By default, the value of the AIGP attribute for a local prefix is zero. An AIGP-enabled neighbor can originate an AIGP attribute for a given prefix by export policy, using the aigp-originate policy action. The value of the AIGP attribute reflects the IGP distance to the prefix. Alternatively, you can specify a value, by using the aigp-originate distance distance policy action. The configurable range is 0 through 4,294,967,295. Only one node needs to originate an AIGP attribute. The AIGP attribute is retained and readvertised if the neighbors are AIGP enabled with the aigp statement in the BGP configuration.
The policy action to originate the AIGP attribute has the following requirements:
Neighbor must be AIGP enabled.
Policy must be applied as an export policy.
Prefix must have no current AIGP attribute.
Prefix must export with next-hop self.
Prefix must reside within the AIGP domain. Typically, a loopback IP address is the prefix to originate.
The policy is ignored if these requirements are not met.
Topology Diagram
Figure 1 shows the topology used in this example. OSPF is used as the interior gateway protocol (IGP). Internal BGP (IBGP) is configured between Device PE1 and Device PE4. External BGP (EBGP) is configured between Device PE7 and Device PE1, between Device PE4 and Device PE3, and between Device PE4 and Device PE2. Devices PE4, PE2, and PE3 are configured for multihop. Device PE4 selects a path based on the AIGP value and then readvertises the AIGP value based on the AIGP and policy configuration. Device PE1 readvertises the AIGP value to Device PE7, which is in another administrative domain. Every device has two loopback interface addresses: 10.9.9.x is used for BGP peering and the router ID, and 10.100.1.x is used for the BGP next hop.
The network between Device PE1 and PE3 has IBGP peering and multiple OSPF areas. The external link to Device PE7 is configured to show that the AIGP attribute is readvertised to a neighbor outside of the administrative domain, if that neighbor is AIGP enabled.
For origination of an AIGP attribute, the BGP next hop is required to be itself. If the BGP next hop remains unchanged, the received AIGP attribute is readvertised, as is, to another AIGP neighbor. If the next hop changes, the received AIGP attribute is readvertised with an increased value to another AIGP neighbor. The increase in value reflects the IGP distance to the previous BGP next hop. To demonstrate, this example uses loopback interface addresses for Device PE4’s EBGP peering sessions with Device PE2 and Device PE3. Multihop is enabled on these sessions so that a recursive lookup is performed to determine the point-to-point interface. Because the next hop changes, the IGP distance is added to the AIGP distance.
Configuration
CLI Quick Configuration
To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level.
Device P1
Device P2
Device PE4
Device PE1
Device PE2
Device PE3
Device PE7
Configuring Device P1
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device P1:
Configure the interfaces.
[edit interfaces]user@P1# set fe-1/2/0 unit 1 description P1-to-PE1user@P1# set fe-1/2/0 unit 1 family inet address 10.0.0.2/30user@P1# set fe-1/2/0 unit 1 family mplsuser@P1# set fe-1/2/1 unit 4 description P1-to-P2user@P1# set fe-1/2/1 unit 4 family inet address 10.0.0.29/30user@P1# set fe-1/2/1 unit 4 family mplsuser@P1# set fe-1/2/2 unit 8 description P1-to-PE4user@P1# set fe-1/2/2 unit 8 family inet address 10.0.0.17/30user@P1# set fe-1/2/2 unit 8 family mplsuser@P1# set lo0 unit 3 family inet address 10.9.9.2/32user@P1# set lo0 unit 3 family inet address 10.100.1.2/32Configure MPLS and a signaling protocol, such as RSVP or LDP.
[edit protocols]user@P1# set rsvp interface fe-1/2/0.1user@P1# set rsvp interface fe-1/2/2.8user@P1# set rsvp interface fe-1/2/1.4user@P1# set mpls label-switched-path P1-to-P2 to 10.9.9.3user@P1# set mpls label-switched-path P1-to-PE1 to 10.9.9.1user@P1# set mpls label-switched-path P1-to-PE4 to 10.9.9.4user@P1# set mpls interface fe-1/2/0.1user@P1# set mpls interface fe-1/2/2.8user@P1# set mpls interface fe-1/2/1.4Configure BGP.
[edit protocols bgp group internal]user@P1# set type internaluser@P1# set local-address 10.9.9.2user@P1# set neighbor 10.9.9.1user@P1# set neighbor 10.9.9.3user@P1# set neighbor 10.9.9.4Enable AIGP.
[edit protocols bgp group internal]user@P1# set family inet labeled-unicast aigpConfigure an IGP, such as OSPF, RIP, or IS-IS.
[edit protocols ospf]user@P1# set area 0.0.0.1 interface fe-1/2/0.1 metric 1user@P1# set area 0.0.0.1 interface fe-1/2/1.4 metric 1user@P1# set area 0.0.0.0 interface fe-1/2/2.8 metric 1user@P1# set area 0.0.0.0 interface 10.9.9.2 passiveuser@P1# set area 0.0.0.0 interface 10.9.9.2 metric 1user@P1# set area 0.0.0.0 interface 10.100.1.2 passiveuser@P1# set area 0.0.0.0 interface 10.100.1.2 metric 1Configure the router ID and the autonomous system number.
[edit routing-options]user@P1# set router-id 10.9.9.2user@P1# set autonomous-system 13979If you are done configuring the device, commit the configuration.
user@P1# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Configuring Device P2
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device P2:
Configure the interfaces.
[edit interfaces]user@P2# set fe-1/2/0 unit 3 description P2-to-PE1user@P2# set fe-1/2/0 unit 3 family inet address 10.0.0.6/30user@P2# set fe-1/2/0 unit 3 family mplsuser@P2# set fe-1/2/1 unit 5 description P2-to-P1user@P2# set fe-1/2/1 unit 5 family inet address 10.0.0.30/30user@P2# set fe-1/2/1 unit 5 family mplsuser@P2# set fe-1/2/2 unit 6 description P2-to-PE4user@P2# set fe-1/2/2 unit 6 family inet address 10.0.0.13/30user@P2# set fe-1/2/2 unit 6 family mplsuser@P2# set lo0 unit 5 family inet address 10.9.9.3/32user@P2# set lo0 unit 5 family inet address 10.100.1.3/32Configure MPLS and a signaling protocol, such as RSVP or LDP.
[edit protocols]user@P2# set rsvp interface fe-1/2/1.5user@P2# set rsvp interface fe-1/2/2.6user@P2# set rsvp interface fe-1/2/0.3user@P2# set mpls label-switched-path P2-to-PE1 to 10.9.9.1user@P2# set mpls label-switched-path P2-to-P1 to 10.9.9.2user@P2# set mpls label-switched-path P2-to-PE4 to 10.9.9.4user@P2# set mpls interface fe-1/2/1.5user@P2# set mpls interface fe-1/2/2.6user@P2# set mpls interface fe-1/2/0.3Configure BGP.
[edit protocols bgp group internal]user@P2# set type internaluser@P2# set local-address 10.9.9.3user@P2# set neighbor 10.9.9.1user@P2# set neighbor 10.9.9.2user@P2# set neighbor 10.9.9.4Enable AIGP.
[edit protocols bgp group internal]user@P2# set family inet labeled-unicast aigpConfigure an IGP, such as OSPF, RIP, or IS-IS.
[edit protocols ospf]user@P2# set area 0.0.0.0 interface fe-1/2/2.6 metric 1user@P2# set area 0.0.0.0 interface 10.9.9.3 passiveuser@P2# set area 0.0.0.0 interface 10.9.9.3 metric 1user@P2# set area 0.0.0.0 interface 10.100.1.3 passiveuser@P2# set area 0.0.0.0 interface 10.100.1.3 metric 1Configure the router ID and the autonomous system number.
[edit routing-options]user@P2# set router-id 10.9.9.3user@P2# set autonomous-system 13979If you are done configuring the device, commit the configuration.
user@P2# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Configuring Device PE4
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device PE4:
Configure the interfaces.
[edit interfaces]user@PE4# set fe-1/2/0 unit 7 description PE4-to-P2user@PE4# set fe-1/2/0 unit 7 family inet address 10.0.0.14/30user@PE4# set fe-1/2/0 unit 7 family mplsuser@PE4# set fe-1/2/1 unit 9 description PE4-to-P1user@PE4# set fe-1/2/1 unit 9 family inet address 10.0.0.18/30user@PE4# set fe-1/2/1 unit 9 family mplsuser@PE4# set fe-1/2/2 unit 10 description PE4-to-PE2user@PE4# set fe-1/2/2 unit 10 family inet address 10.0.0.21/30user@PE4# set fe-1/2/2 unit 10 family mplsuser@PE4# set fe-1/0/2 unit 12 description PE4-to-PE3user@PE4# set fe-1/0/2 unit 12 family inet address 10.0.0.25/30user@PE4# set fe-1/0/2 unit 12 family mplsuser@PE4# set lo0 unit 7 family inet address 10.9.9.4/32user@PE4# set lo0 unit 7 family inet address 10.100.1.4/32Configure MPLS and a signaling protocol, such as RSVP or LDP.
[edit protocols]user@PE4# set rsvp interface fe-1/2/0.7user@PE4# set rsvp interface fe-1/2/1.9user@PE4# set rsvp interface fe-1/2/2.10user@PE4# set rsvp interface fe-1/0/2.12user@PE4# set mpls label-switched-path PE4-to-PE2 to 10.9.9.5user@PE4# set mpls label-switched-path PE4-to-PE3 to 10.9.9.6user@PE4# set mpls label-switched-path PE4-to-P1 to 10.9.9.2user@PE4# set mpls label-switched-path PE4-to-P2 to 10.9.9.3user@PE4# set mpls interface fe-1/2/0.7user@PE4# set mpls interface fe-1/2/1.9user@PE4# set mpls interface fe-1/2/2.10user@PE4# set mpls interface fe-1/0/2.12Configure BGP.
[edit protocols bgp]user@PE4# set export next-hopuser@PE4# set export aigpuser@PE4# set group internal type internaluser@PE4# set group internal local-address 10.9.9.4user@PE4# set group internal neighbor 10.9.9.1user@PE4# set group internal neighbor 10.9.9.3user@PE4# set group internal neighbor 10.9.9.2user@PE4# set group external type externaluser@PE4# set group external multihop ttl 2user@PE4# set group external local-address 10.9.9.4user@PE4# set group external peer-as 7018user@PE4# set group external neighbor 10.9.9.5user@PE4# set group external neighbor 10.9.9.6Enable AIGP.
[edit protocols bgp]user@PE4# set group external family inet labeled-unicast aigpuser@PE4# set group internal family inet labeled-unicast aigpOriginate a prefix, and configure an AIGP distance.
By default, a prefix is originated using the current IGP distance. Optionally, you can configure a distance for the AIGP attribute, using the distance option, as shown here.
[edit policy-options policy-statement aigp term 10]user@PE4# set from protocol staticuser@PE4# set from route-filter 44.0.0.0/24 exactuser@PE4# set then aigp-originate distance 200user@PE4# set then next-hop 10.100.1.4user@PE4# set then acceptEnable the policies.
[edit policy-options policy-statement next-hop]user@PE4# set term 10 from protocol bgpuser@PE4# set term 10 then next-hop 10.100.1.4user@PE4# set term 10 then acceptuser@PE4# set term 20 from protocol directuser@PE4# set term 20 from route-filter 10.9.9.4/32 exactuser@PE4# set term 20 from route-filter 10.100.1.4/32 exactuser@PE4# set term 20 then next-hop 10.100.1.4user@PE4# set term 20 then acceptConfigure a static route.
[edit routing-options]user@PE4# set static route 44.0.0.0/24 discardConfigure an IGP, such as OSPF, RIP, or IS-IS.
[edit protocols ospf]user@PE4# set area 0.0.0.0 interface fe-1/2/1.9 metric 1user@PE4# set area 0.0.0.0 interface fe-1/2/0.7 metric 1user@PE4# set area 0.0.0.0 interface 10.9.9.4 passiveuser@PE4# set area 0.0.0.0 interface 10.9.9.4 metric 1user@PE4# set area 0.0.0.0 interface 10.100.1.4 passiveuser@PE4# set area 0.0.0.0 interface 10.100.1.4 metric 1user@PE4# set area 0.0.0.2 interface fe-1/2/2.10 metric 1user@PE4# set area 0.0.0.3 interface fe-1/0/2.12 metric 1Configure the router ID and the autonomous system number.
[edit routing-options]user@PE4# set router-id 10.9.9.4user@PE4# set autonomous-system 13979If you are done configuring the device, commit the configuration.
user@PE4# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show policy-options, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Configuring Device PE1
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device PE1:
Configure the interfaces.
[edit interfaces]user@PE1# set fe-1/2/0 unit 0 description PE1-to-P1user@PE1# set fe-1/2/0 unit 0 family inet address 10.0.0.1/30user@PE1# set fe-1/2/0 unit 0 family mplsuser@PE1# set fe-1/2/1 unit 2 description PE1-to-P2user@PE1# set fe-1/2/1 unit 2 family inet address 10.0.0.5/30user@PE1# set fe-1/2/1 unit 2 family mplsuser@PE1# set fe-1/2/2 unit 14 description PE1-to-PE7user@PE1# set fe-1/2/2 unit 14 family inet address 10.0.0.9/30user@PE1# set lo0 unit 1 family inet address 10.9.9.1/32user@PE1# set lo0 unit 1 family inet address 10.100.1.1/32Configure MPLS and a signaling protocol, such as RSVP or LDP.
[edit protocols]user@PE1# set rsvp interface fe-1/2/0.0user@PE1# set rsvp interface fe-1/2/1.2user@PE1# set rsvp interface fe-1/2/2.14user@PE1# set mpls label-switched-path PE1-to-P1 to 10.9.9.2user@PE1# set mpls label-switched-path PE1-to-P2 to 10.9.9.3user@PE1# set mpls interface fe-1/2/0.0user@PE1# set mpls interface fe-1/2/1.2user@PE1# set mpls interface fe-1/2/2.14Configure BGP.
[edit protocols bgp]user@PE1# set group internal type internaluser@PE1# set group internal local-address 10.9.9.1user@PE1# set group internal export SET_EXPORT_ROUTESuser@PE1# set group internal vpn-apply-exportuser@PE1# set group internal neighbor 10.9.9.4user@PE1# set group internal neighbor 10.9.9.2user@PE1# set group internal neighbor 10.9.9.3user@PE1# set group external type externaluser@PE1# set group external export SET_EXPORT_ROUTESuser@PE1# set group external peer-as 7019user@PE1# set group external neighbor 10.0.0.10Enable AIGP.
[edit protocols bgp]user@PE1# set group internal family inet labeled-unicast aigpuser@PE1# set group external family inet labeled-unicast aigpEnable the policies.
[edit policy-options policy-statement SET_EXPORT_ROUTES term 10]user@PE1# set from protocol directuser@PE1# set from protocol bgpuser@PE1# set then next-hop 10.100.1.1user@PE1# set then acceptConfigure an IGP, such as OSPF, RIP, or IS-IS.
[edit protocols ospf area 0.0.0.1]user@PE1# set interface fe-1/2/0.0 metric 1user@PE1# set interface fe-1/2/1.2 metric 1user@PE1# set interface 10.9.9.1 passiveuser@PE1# set interface 10.9.9.1 metric 1user@PE1# set interface 10.100.1.1 passiveuser@PE1# set interface 10.100.1.1 metric 1Configure the router ID and the autonomous system number.
[edit routing-options]user@PE1# set router-id 10.9.9.1user@PE1# set autonomous-system 13979If you are done configuring the device, commit the configuration.
user@PE1# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show policy-options, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Configuring Device PE2
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device PE2:
Configure the interfaces.
[edit interfaces]user@PE2# set fe-1/2/0 unit 11 description PE2-to-PE4user@PE2# set fe-1/2/0 unit 11 family inet address 10.0.0.22/30user@PE2# set fe-1/2/0 unit 11 family mplsuser@PE2# set lo0 unit 9 family inet address 10.9.9.5/32 primaryuser@PE2# set lo0 unit 9 family inet address 10.100.1.5/32Configure MPLS and a signaling protocol, such as RSVP or LDP.
[edit protocols]user@PE2# set rsvp interface fe-1/2/0.11user@PE2# set mpls label-switched-path PE2-to-PE4 to 10.9.9.4user@PE2# set mpls interface fe-1/2/0.11Configure BGP.
[edit protocols bgp]user@PE2# set group external type externaluser@PE2# set group external multihop ttl 2user@PE2# set group external local-address 10.9.9.5user@PE2# set group external export next-hopuser@PE2# set group external export aigpuser@PE2# set group external export SET_EXPORT_ROUTESuser@PE2# set group external vpn-apply-exportuser@PE2# set group external peer-as 13979user@PE2# set group external neighbor 10.9.9.4Enable AIGP.
[edit protocols bgp]user@PE2# set group external family inet labeled-unicast aigpOriginate a prefix, and configure an AIGP distance.
By default, a prefix is originated using the current IGP distance. Optionally, you can configure a distance for the AIGP attribute, using the distance option, as shown here.
[edit policy-options policy-statement aigp]user@PE2# set term 10 from route-filter 55.0.0.0/24 exactuser@PE2# set term 10 then aigp-originate distance 20user@PE2# set term 10 then next-hop 10.100.1.5user@PE2# set term 10 then acceptuser@PE2# set term 20 from route-filter 99.0.0.0/24 exactuser@PE2# set term 20 then aigp-originate distance 30user@PE2# set term 20 then next-hop 10.100.1.5user@PE2# set term 20 then acceptEnable the policies.
[edit policy-options]user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 from protocol directuser@PE2# set policy-statement SET_EXPORT_ROUTES term 10 from protocol staticuser@PE2# set policy-statement SET_EXPORT_ROUTES term 10 from protocol bgpuser@PE2# set policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.5user@PE2# set policy-statement SET_EXPORT_ROUTES term 10 then acceptuser@PE2# set policy-statement next-hop term 10 from protocol bgpuser@PE2# set policy-statement next-hop term 10 then next-hop 10.100.1.5user@PE2# set policy-statement next-hop term 10 then acceptuser@PE2# set policy-statement next-hop term 20 from protocol directuser@PE2# set policy-statement next-hop term 20 from route-filter 10.9.9.5/32 exactuser@PE2# set policy-statement next-hop term 20 from route-filter 10.100.1.5/32 exactuser@PE2# set policy-statement next-hop term 20 then next-hop 10.100.1.5user@PE2# set policy-statement next-hop term 20 then acceptEnable some static routes.
[edit routing-options]user@PE2# set static route 99.0.0.0/24 discarduser@PE2# set static route 55.0.0.0/24 discardConfigure an IGP, such as OSPF, RIP, or IS-IS.
[edit protocols ospf area 0.0.0.2]user@PE2# set interface 10.9.9.5 passiveuser@PE2# set interface 10.9.9.5 metric 1user@PE2# set interface 10.100.1.5 passiveuser@PE2# set interface 10.100.1.5 metric 1user@PE2# set interface fe-1/2/0.11 metric 1Configure the router ID and the autonomous system number.
[edit routing-options]user@PE2# set router-id 10.9.9.5user@PE2# set autonomous-system 7018If you are done configuring the device, commit the configuration.
user@PE2# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show policy-options, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Configuring Device PE3
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device PE3:
Configure the interfaces.
[edit interfaces]user@PE3# set fe-1/2/0 unit 13 description PE3-to-PE4user@PE3# set fe-1/2/0 unit 13 family inet address 10.0.0.26/30user@PE3# set fe-1/2/0 unit 13 family mplsuser@PE3# set lo0 unit 11 family inet address 10.9.9.6/32user@PE3# set lo0 unit 11 family inet address 10.100.1.6/32Configure MPLS and a signaling protocol, such as RSVP or LDP.
[edit protocols]user@PE3# set rsvp interface fe-1/2/0.13user@PE3# set mpls label-switched-path PE3-to-PE4 to 10.9.9.4user@PE3# set mpls interface fe-1/2/0.13Configure BGP.
[edit protocols bgp group external]user@PE3# set type externaluser@PE3# set multihop ttl 2user@PE3# set local-address 10.9.9.6user@PE3# set export next-hopuser@PE3# set export SET_EXPORT_ROUTESuser@PE3# set vpn-apply-exportuser@PE3# set peer-as 13979user@PE3# set neighbor 10.9.9.4Enable AIGP.
[edit protocols bgp group external]user@PE3# set family inet labeled-unicast aigpEnable the policies.
[edit policy-options]user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 from protocol directuser@PE3# set policy-statement SET_EXPORT_ROUTES term 10 from protocol staticuser@PE3# set policy-statement SET_EXPORT_ROUTES term 10 from protocol bgpuser@PE3# set policy-statement SET_EXPORT_ROUTES term 10 then next-hop 10.100.1.6user@PE3# set policy-statement SET_EXPORT_ROUTES term 10 then acceptuser@PE3# set policy-statement next-hop term 10 from protocol bgpuser@PE3# set policy-statement next-hop term 10 then next-hop 10.100.1.6user@PE3# set policy-statement next-hop term 10 then acceptuser@PE3# set policy-statement next-hop term 20 from protocol directuser@PE3# set policy-statement next-hop term 20 from route-filter 10.9.9.6/32 exactuser@PE3# set policy-statement next-hop term 20 from route-filter 10.100.1.6/32 exactuser@PE3# set policy-statement next-hop term 20 then next-hop 10.100.1.6user@PE3# set policy-statement next-hop term 20 then acceptConfigure an IGP, such as OSPF, RIP, or IS-IS.
[edit protocols ospf area 0.0.0.3]user@PE3# set interface 10.9.9.6 passiveuser@PE3# set interface 10.9.9.6 metric 1user@PE3# set interface 10.100.1.6 passiveuser@PE3# set interface 10.100.1.6 metric 1user@PE3# set interface fe-1/2/0.13 metric 1Configure the router ID and the autonomous system number.
[edit routing-options]user@PE3# set router-id 10.9.9.6user@PE3# set autonomous-system 7018If you are done configuring the device, commit the configuration.
user@PE3# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show policy-options, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Configuring Device PE7
Step-by-Step Procedure
The following example requires you to navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.
To configure Device PE7:
Configure the interfaces.
[edit interfaces]user@PE7# set fe-1/2/0 unit 15 description PE7-to-PE1user@PE7# set fe-1/2/0 unit 15 family inet address 10.0.0.10/30user@PE7# set lo0 unit 13 family inet address 10.9.9.7/32user@PE7# set lo0 unit 13 family inet address 10.100.1.7/32Configure BGP.
[edit protocols bgp group external]user@PE7# set type externaluser@PE7# set export SET_EXPORT_ROUTESuser@PE7# set peer-as 13979user@PE7# set neighbor 10.0.0.9Enable AIGP.
[edit protocols bgp group external]user@PE7# set family inet labeled-unicast aigp- Configure the routing policy.[edit policy-options policy-statement SET_EXPORT_ROUTES term 10]user@PE7# set from protocol directuser@PE7# set from protocol bgpuser@PE7# set then next-hop 10.100.1.7user@PE7# set then accept
Configure the router ID and the autonomous system number.
[edit routing-options]user@PE7# set router-id 10.9.9.7user@PE7# set autonomous-system 7019If you are done configuring the device, commit the configuration.
user@PE7# commit
Results
From configuration mode, confirm your configuration by entering the show interfaces, show policy-options, show protocols, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.
Verification
Confirm that the configuration is working properly.
Verifying That Device PE4 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE2
Verifying That Device PE4 Adds the IGP Metric to the AIGP Attribute
Verifying That Device PE7 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE1
Verifying That Device PE4 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE2
Purpose
Make sure that the AIGP policy on Device PE2 is working.
Action
user@PE4> show route receive-protocol bgp 10.9.9.5
extensive* 55.0.0.0/24 (1 entry, 1 announced)
Accepted
Route Label: 299888
Nexthop: 10.100.1.5
AS path: 7018 I
AIGP: 20
* 99.0.0.0/24 (1 entry, 1 announced)
Accepted
Route Label: 299888
Nexthop: 10.100.1.5
AS path: 7018 I
AIGP: 30Meaning
On Device PE2, the aigp-originate statement is configured with a distance of 20 (aigp-originate distance 20). This statement is applied to route 55.0.0.0/24. Likewise, the aigp-originate distance 30 statement is applied to route 99.0.0.0/24. Thus, when Device PE4 receives these routes, the AIGP attribute is attached with the configured metrics.
Checking the IGP Metric
Purpose
From Device PE4, check the IGP metric to the BGP next hop 10.100.1.5.
Action
user@PE4> show route 10.100.1.5inet.0: 30 destinations, 40 routes (30 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
10.100.1.5/32 *[OSPF/10] 05:35:50, metric 2
> to 10.0.0.22 via fe-1/2/2.10
[BGP/170] 03:45:07, localpref 100, from 10.9.9.5
AS path: 7018 I
> to 10.0.0.22 via fe-1/2/2.10
Meaning
The IGP metric for this route is 2.
Verifying That Device PE4 Adds the IGP Metric to the AIGP Attribute
Purpose
Make sure that Device PE4 adds the IGP metric to the AIGP attribute when it readvertises routes to its IBGP neighbor, Device PE1.
Action
user@PE4> show route advertising-protocol bgp
10.9.9.1 extensive
* 55.0.0.0/24 (1 entry, 1 announced)
BGP group internal type Internal
Route Label: 300544
Nexthop: 10.100.1.4
Flags: Nexthop Change
Localpref: 100
AS path: [13979] 7018 I
AIGP: 22
* 99.0.0.0/24 (1 entry, 1 announced)
BGP group internal type Internal
Route Label: 300544
Nexthop: 10.100.1.4
Flags: Nexthop Change
Localpref: 100
AS path: [13979] 7018 I
AIGP: 32Meaning
The IGP metric is added to the AIGP metric (20 + 2 = 22 and 30 + 2 = 32), because the next hop is changed for these routes.
Verifying That Device PE7 Is Receiving the AIGP Attribute from Its EBGP Neighbor PE1
Purpose
Make sure that the AIGP policy on Device PE1 is working.
Action
user@PE7> show route receive-protocol bgp 10.0.0.9
extensive* 44.0.0.0/24 (1 entry, 1 announced)
Accepted
Route Label: 300096
Nexthop: 10.0.0.9
AS path: 13979 I
AIGP: 203
* 55.0.0.0/24 (1 entry, 1 announced)
Accepted
Route Label: 300112
Nexthop: 10.0.0.9
AS path: 13979 7018 I
AIGP: 25
* 99.0.0.0/24 (1 entry, 1 announced)
Accepted
Route Label: 300112
Nexthop: 10.0.0.9
AS path: 13979 7018 I
AIGP: 35Meaning
The 44.0.0.0/24 route is originated at Device PE4. The 55.0.0.0/24 and 99.0.0.0/24 routes are originated at Device PE2. The IGP distances are added to the configured AIGP distances.
Verifying the Resolving AIGP Metric
Purpose
Confirm that if the prefix is resolved through recursion and the recursive next hops have AIGP metrics, the prefix has the sum of the AIGP values that are on the recursive BGP next hops.
Action
Add a static route to 66.0.0.0/24.
[edit routing-options]user@PE2# set static route 66.0.0.0/24 discardDelete the existing terms in the aigp policy statement on Device PE2.
[edit policy-options policy-statement aigp]user@PE2# delete term 10user@PE2# delete term 20Configure a recursive route lookup for the route to 66.0.0.0.
The policy shows the AIGP metric for prefix 66.0.0.0/24 (none) and its recursive next hop. Prefix 66.0.0.0/24 is resolved by 55.0.0.1. Prefix 66.0.0.0/24 does not have its own AIGP metric being originated, but its recursive next hop, 55.0.0.1, has an AIGP value.
[edit policy-options policy-statement aigp]user@PE2# set term 10 from route-filter 55.0.0.1/24 exactuser@PE2# set term 10 then aigp-originate distance 20user@PE2# set term 10 then next-hop 10.100.1.5user@PE2# set term 10 then acceptuser@PE2# set term 20 from route-filter 66.0.0.0/24 exactuser@PE2# set term 20 then next-hop 55.0.0.1user@PE2# set term 20 then acceptOn Device PE4, run the show route 55.0.0.0 extensive command.
The value of Metric2 is the IGP metric to the BGP next hop. When Device PE4 readvertises these routes to its IBGP peer, Device PE1, the AIGP metric is the sum of AIGP + its Resolving AIGP metric + Metric2.
Prefix 55.0.0.0 shows its own IGP metric 20, as defined and advertised by Device PE2. It does not show a resolving AIGP value because it does not have a recursive BGP next hop. The value of Metric2 is 2.
user@PE4> show route 55.0.0.0 extensiveinet.0: 31 destinations, 41 routes (31 active, 0 holddown, 0 hidden) 55.0.0.0/24 (1 entry, 1 announced) TSI: KRT in-kernel 55.0.0.0/24 -> {indirect(262151)} Page 0 idx 0 Type 1 val 928d1b8 Flags: Nexthop Change Nexthop: 10.100.1.4 Localpref: 100 AS path: [13979] 7018 I Communities: AIGP: 22 Path 55.0.0.0 from 10.9.9.5 Vector len 4. Val: 0 *BGP Preference: 170/-101 Next hop type: Indirect Address: 0x925da38 Next-hop reference count: 4 Source: 10.9.9.5 Next hop type: Router, Next hop index: 1004 Next hop: 10.0.0.22 via fe-1/2/2.10, selected Label operation: Push 299888 Label TTL action: prop-ttl Protocol next hop: 10.100.1.5 Push 299888 Indirect next hop: 93514d8 262151 State: <Active Ext> Local AS: 13979 Peer AS: 7018 Age: 22:03:26 Metric2: 2 AIGP: 20 Task: BGP_7018.10.9.9.5+58560 Announcement bits (3): 3-KRT 4-BGP_RT_Background 5-Resolve tree 1 AS path: 7018 I Accepted Route Label: 299888 Localpref: 100 Router ID: 10.9.9.5 Indirect next hops: 1 Protocol next hop: 10.100.1.5 Metric: 2 Push 299888 Indirect next hop: 93514d8 262151 Indirect path forwarding next hops: 1 Next hop type: Router Next hop: 10.0.0.22 via fe-1/2/2.10 10.100.1.5/32 Originating RIB: inet.0 Metric: 2 Node path count: 1 Forwarding nexthops: 1 Nexthop: 10.0.0.22 via fe-1/2/2.10On Device PE4, run the show route 66.0.0.0 extensive command.
Prefix 66.0.0.0/24 shows the Resolving AIGP, which is the sum of its own AIGP metric and its recursive BGP next hop:
66.0.0.1 = 0, 55.0.0.1 = 20, 0+20 = 20
user@PE4> show route 66.0.0.0 extensiveinet.0: 31 destinations, 41 routes (31 active, 0 holddown, 0 hidden) 66.0.0.0/24 (1 entry, 1 announced) TSI: KRT in-kernel 66.0.0.0/24 -> {indirect(262162)} Page 0 idx 0 Type 1 val 928cefc Flags: Nexthop Change Nexthop: 10.100.1.4 Localpref: 100 AS path: [13979] 7018 I Communities: Path 66.0.0.0 from 10.9.9.5 Vector len 4. Val: 0 *BGP Preference: 170/-101 Next hop type: Indirect Address: 0x925d4e0 Next-hop reference count: 4 Source: 10.9.9.5 Next hop type: Router, Next hop index: 1006 Next hop: 10.0.0.22 via fe-1/2/2.10, selected Label operation: Push 299888, Push 299888(top) Label TTL action: prop-ttl, prop-ttl(top) Protocol next hop: 55.0.0.1 Push 299888 Indirect next hop: 9353e88 262162 State: <Active Ext> Local AS: 13979 Peer AS: 7018 Age: 31:42 Metric2: 2 Resolving-AIGP: 20 Task: BGP_7018.10.9.9.5+58560 Announcement bits (3): 3-KRT 4-BGP_RT_Background 5-Resolve tree 1 AS path: 7018 I Accepted Route Label: 299888 Localpref: 100 Router ID: 10.9.9.5 Indirect next hops: 1 Protocol next hop: 55.0.0.1 Metric: 2 AIGP: 20 Push 299888 Indirect next hop: 9353e88 262162 Indirect path forwarding next hops: 1 Next hop type: Router Next hop: 10.0.0.22 via fe-1/2/2.10 55.0.0.0/24 Originating RIB: inet.0 Metric: 2 Node path count: 1 Indirect nexthops: 1 Protocol Nexthop: 10.100.1.5 Metric: 2 Push 299888 Indirect nexthop: 93514d8 262151 Indirect path forwarding nexthops: 1 Nexthop: 10.0.0.22 via fe-1/2/2.10 10.100.1.5/32 Originating RIB: inet.0 Metric: 2 Node path count: 1 Forwarding nexthops: 1 Nexthop: 10.0.0.22 via fe-1/2/2.10
Verifying the Presence of AIGP Attributes in BGP Updates
Purpose
If the AIGP attribute is not enabled under BGP (or the group or neighbor hierarchies), the AIGP attribute is silently discarded. Enable traceoptions and include the packets flag in the detail option in the configuration to confirm the presence of the AIGP attribute in transmitted or received BGP updates. This is useful when debugging AIGP issues.
Action
Configure Device PE2 and Device PE4 for traceoptions.
user@host> show protocols bgptraceoptions {file bgp size 1m files 5;flag packets detail;}Check the traceoptions file on Device PE2.
The following sample shows Device PE2 advertising prefix 99.0.0.0/24 to Device PE4 (10.9.9.4) with an AIGP metric of 20:
user@PE2> show log bgpMar 22 09:27:18.982150 BGP SEND 10.9.9.5+49652 -> 10.9.9.4+179 Mar 22 09:27:18.982178 BGP SEND message type 2 (Update) length 70 Mar 22 09:27:18.982198 BGP SEND Update PDU length 70 Mar 22 09:27:18.982248 BGP SEND flags 0x40 code Origin(1): IGP Mar 22 09:27:18.982273 BGP SEND flags 0x40 code ASPath(2) length 6: 7018 Mar 22 09:27:18.982295 BGP SEND flags 0x80 code AIGP(26): AIGP: 20 Mar 22 09:27:18.982316 BGP SEND flags 0x90 code MP_reach(14): AFI/SAFI 1/4 Mar 22 09:27:18.982341 BGP SEND nhop 10.100.1.5 len 4 Mar 22 09:27:18.982372 BGP SEND 99.0.0.0/24 (label 301664) Mar 22 09:27:33.665412 bgp_send: sending 19 bytes to abcd::10:255:170:84 (External AS 13979)
Verify that the route was received on Device PE4 using the show route receive-protocol command.
AIGP is not enabled on Device PE4, so the AIGP attribute is silently discarded for prefix 99.0.0.0/24 and does not appear in the following output:
user@PE4> show route receive-protocol bgp 10.9.9.5 extensive | find 55.0.0.0* 99.0.0.0/24 (2 entries, 1 announced) Accepted Route Label: 301728 Nexthop: 10.100.1.5 AS path: 7018 ICheck the traceoptions file on Device PE4.
The following output from the traceoptions log shows that the 99.0.0.0/24 prefix was received with the AIGP attribute attached:
user@PE4> show log bgpMar 22 09:41:39.650295 BGP RECV 10.9.9.5+64690 -> 10.9.9.4+179 Mar 22 09:41:39.650331 BGP RECV message type 2 (Update) length 70 Mar 22 09:41:39.650350 BGP RECV Update PDU length 70 Mar 22 09:41:39.650370 BGP RECV flags 0x40 code Origin(1): IGP Mar 22 09:41:39.650394 BGP RECV flags 0x40 code ASPath(2) length 6: 7018 Mar 22 09:41:39.650415 BGP RECV flags 0x80 code AIGP(26): AIGP: 20 Mar 22 09:41:39.650436 BGP RECV flags 0x90 code MP_reach(14): AFI/SAFI 1/4 Mar 22 09:41:39.650459 BGP RECV nhop 10.100.1.5 len 4 Mar 22 09:41:39.650495 BGP RECV 99.0.0.0/24 (label 301728) Mar 22 09:41:39.650574 bgp_rcv_nlri: 99.0.0.0/24 Mar 22 09:41:39.650607 bgp_rcv_nlri: 99.0.0.0/24 belongs to meshgroup Mar 22 09:41:39.650629 bgp_rcv_nlri: 99.0.0.0/24 qualified bnp->ribact 0x0 l2afcb 0x0
Meaning
Performing this verification helps with AIGP troubleshooting and debugging issues. It enables you to verify which devices in your network send and receive AIGP attributes.