2.11. Configuring an IP Router with CLI
This section provides information to configure an IP router using CLI.
2.11.1. Router Configuration Overview
In a Nokia router, an interface is a logical named entity. An interface is created by specifying an interface name under the config>router context. This is the global router configuration context where objects like static routes are defined. An IP interface name can be up to 32 alphanumeric characters, must start with a letter, and is case-sensitive; for example, the interface name “1.1.1.1” is not allowed, but “int-1.1.1.1” is allowed.
To create an interface, the following basic configuration tasks must be performed.
- Assign a name to the interface.
- Associate an IP address with the interface.
- Associate the interface with a network interface or the system interface.
- Configure appropriate routing protocols.
A system interface and network interface must be configured.
2.11.1.1. System Interface
The system interface is associated with a network entity (such as a specific Nokia router), not a specific interface. The system interface is also referred to as the loopback address. The system interface is associated during the configuration of the following entities:
- Termination point of service tunnels
- Hops when configuring MPLS paths and LSPs
- Addresses on a target router for BGP and LDP peering
The system interface is used to preserve connectivity (when routing reconvergence is possible) when an interface fails or is removed. The system interface is used as the router identifier. A system interface must have an IP address with a 32-bit subnet mask.
2.11.1.2. Network Interface
A network interface can be configured on one of the following entities:
- Physical or logical port
- SONET/SDH channel
For the 7950 XRS, a network interface can be configured on either a physical port or Ethernet LAG interface.
2.11.2. Basic Configuration
Refer to each specific chapter for specific routing protocol information and command syntax to configure protocols such as OSPF and BGP.
The most basic router configuration must have the following:
- System name
- System address
The following example shows a router configuration for the 7750 SR and 7450 ESS:
2.11.3. Common Configuration Tasks
The following sections describe basic system tasks.
2.11.3.1. Configuring a System Name
Use the system command to configure a name for the device. The name is used in the prompt string. Only one system name can be configured. If multiple system names are configured, the last one configured will overwrite the previous entry.
If special characters are included in the system name string, such as spaces, #, or ?, the entire string must be enclosed in double quotes. To configure the system name:
The following example shows the system name output:
2.11.3.2. Configuring Interfaces
The following command sequences create a system and a logical IP interface. The system interface assigns an IP address to the interface, then associates the IP interface with a physical port. The logical interface can associate attributes like an IP address or port.
The system interface cannot be deleted.
2.11.3.2.1. Configuring a System Interface
To configure a system interface:
2.11.3.2.2. Configuring a Network Interface
To configure a network interface for the 7450 ESS:
To configure a network interface for the 7750 SR:
To configure a network interface on the 7950 XRS:
The following shows interface information about an IP configuration:
To enable CPU protection:
CPU protection policies are configured in the config>sys>security>cpu-protection context. Refer to the 7450 ESS, 7750 SR, 7950 XRS, and VSR System Management Guide.
2.11.3.2.3. Assigning a Key Group to a Router Interface
Use the following CLI syntax to assign a key group to a router interface:
The following example displays a key group assigned to a router interface:
The following example displays key group configuration for a router interface.
2.11.3.2.4. Configuring IPv6 Parameters
IPv6 interfaces and associated routing protocols may only be configured on the following systems:
- 7950 XRS systems.
- 7750 SR chassis systems.
- 7750 SR-a chassis systems.
- 7750 SR-e chassis systems.
- 7450 ESS chassis running in mixed-mode, with IPv6 functionality limited to those interfaces on slots with 7750 IOM3-XPs/IMMs (or later) line card.
- 7750 SR-c4/12.
The following displays the interface configuration showing the IPv6 default configuration when IPv6 is enabled on the interface:
To configure IPv6 parameters on a router interface:
The following displays a configuration example showing interface information:
2.11.3.2.5. Configuring IPv6 Over IPv4 Parameters
The following sections provide several examples of the features that must be configured (tunnel ingress and egress node) to implement IPv6 over IPv4 relay services for the 7750 SR OS.
2.11.3.2.6. Tunnel Ingress Node
The following example shows the configuration of the interface through which the IPv6 over IPv4 traffic leaves the node. This must be configured on a network interface.
The following example shows an interface configuration:
Both the IPv4 and IPv6 system addresses must be configured:
The following example shows the configuration of interface information:
2.11.3.2.6.1. Learning the Tunnel Endpoint IPv4 System Address
The following example shows the OSPF configuration to learn the IPv4 system address of the tunnel endpoint:
The following example shows the configuration of OSPF output:
2.11.3.2.6.2. Configuring an IPv4 BGP Peer
The following example shows the configuration of an IPv4 BGP peer with (IPv4 and) IPv6 protocol families:
The following example shows the configuration of BGP output:
2.11.3.2.6.3. An Example of an IPv6 Over IPv4 Tunnel Configuration
The IPv6 address is the next-hop as it is received through BGP. The IPv4 address is the system address of the tunnel's endpoint.
The following example shows the configuration of a policy to export IPv6 routes into BGP:
The following example shows the configuration output:
2.11.3.2.7. Tunnel Egress Node
The following example shows the configuration of the interface through which the IPv6 over IPv4 traffic leaves the node. It must be configured on a network interface. Both the IPv4 and IPv6 system addresses must be configured.
The following example shows the interface configuration:
2.11.3.2.7.1. Learning the Tunnel Endpoint IPv4 System Address
The following example shows the configuration of the OSPF configuration to learn the IPv4 system address of the tunnel endpoint:
The following example shows the configuration of OSPF information:
2.11.3.2.7.2. Configuring an IPv4 BGP Peer
The following example shows the configuration an IPv4 BGP peer with (IPv4 and) IPv6 protocol families:
The following example shows the IPv4 BGP peer configuration:
2.11.3.2.7.3. An Example of an IPv6 Over IPv4 Tunnel Configuration
The IPv6 address is the next-hop as it is received through BGP. The IPv4 address is the system address of the tunnel's endpoint.
The following example shows the configuration of a policy to export IPv6 routes into BGP:
The following example shows an IPv6 over IPv4 tunnel configuration:
2.11.3.2.8. Router Advertisement
To configure the router to originate router advertisement messages on an interface, the interface must be configured under the router-advertisement context and be enabled (no shutdown). All other router advertisement configuration parameters are optional.
Router advertisement can be configured under the config>router>router-advertisement context or under the config>service>vprn>router-advertisement context. Use the following examples of CLI syntax to enable router advertisement and configure router advertisement parameters.
To configure router advertisement on the 7750 SR:
To configure router advertisement for the 7450 ESS:
The following example shows a router advertisement configuration:
2.11.3.2.9. Configuring IPv6 Parameters
The following example shows the IPv6 default configuration when IPv6 is enabled on the interface:
The following example shows an IPv6 configuration:
2.11.3.2.9.1. An Example of an IPv6 Over IPv4 Tunnel Configuration
The IPv6 address is the next-hop as it is received through BGP. The IPv4 address is the system address of the tunnel's endpoint.
The following example shows the configuration of a policy to export IPv6 routes into BGP:
The following example shows the configuration of the policy output:
2.11.3.2.10. Configuring Proxy ARP
To configure proxy ARP, you can configure:
- A prefix list in the config>router>policy-options>prefix-list context.
- A route policy statement in the config>router>policy-options>policy-statement context and apply the specified prefix list.
- In the policy statement entry>to context, specify the host source address(es) for which ARP requests can or cannot be forwarded to non-local networks, depending on the specified action.
- In the policy statement entry>from context, specify network prefixes that ARP requests will or will not be forwarded to depending on the action if a match is found. For more information about route policies, refer to the 7450 ESS, 7750 SR, 7950 XRS, and VSR Unicast Routing Protocols Guide.
- Apply the policy statement to the proxy-arp configuration in the config>router>interface context.
To configure the policy statement specified in the proxy-arp-policy policy-statement command:
The following example shows the prefix list and policy statement configuration:
Use the following CLI to configure proxy ARP:
The following example shows a proxy ARP configuration:
2.11.3.2.11. Creating an IP Address Range
An IP address range can be reserved for exclusive use for services by defining the config>router>service-prefix command. When the service is configured, the IP address must be in the range specified as a service prefix. If no service prefix command is configured, no limitation exists.
The no service-prefix ip-prefix/mask command removes all address reservations. A service prefix cannot be removed while one or more services use address(es) in the range to be removed.
2.11.3.3. Deriving the Router ID
The router ID defaults to the address specified in the system interface command. If the system interface is not configured with an IP address, the router ID inherits the last four bytes of the MAC address. The router ID can also be manually configured in the config>router router-id context. On the BGP protocol level, a BGP router ID can be defined in the config>router>bgp router-id context and is only used within BGP.
If a new router ID is configured, protocols are not automatically restarted with the new router ID. The next time a protocol is initialized, the new router ID is used. An interim period of time can occur when different protocols use different router IDs. To force the new router ID, issue the shutdown and no shutdown commands for each protocol that uses the router ID, or restart the entire router.
It is possible to configure SR OS to operate with an IPv6 only BOF and no IPv4 system interface address. When configured in this manner, the operator must explicitly define IPv4 router IDs for protocols such as OSPF and BGP because there is no mechanism to derive the router ID from an IPv6 system interface address.
To configure the router ID:
The following example shows a router ID configuration:
2.11.3.4. Configuring a Confederation
Configuring a confederation is optional. The AS and confederation topology design should be carefully planned. Autonomous system (AS), confederation, and BGP connection and peering parameters must be explicitly created on each participating router. Identify AS numbers, confederation numbers, and members participating in the confederation.
See the BGP section for CLI syntax and command descriptions.
To configure a confederation:
The following example shows the configuration of the confederation topology in Figure 2.
 | Note:
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The following example shows a confederation configuration:
2.11.3.5. Configuring an Autonomous System
Configuring an autonomous system is optional. To configure an autonomous system:
The following example shows an autonomous system configuration:
2.11.3.6. Configuring Overload State on a Single SFM
When a router has fewer than the full set of SFMs functioning, the forwarding capacity can be reduced. Some scenarios include:
- fewer than the maximum number of SFMs installed in the system
- one or more SFMs have failed
- the system is in the ISSU process and the SFM is co-located on the CPM
An overload condition can be set for IS-IS and OSPF to enable the router to still participate in exchanging routing information, but route all traffic away from it when insufficient SFMs are active. This is achieved using the following CLI commands:
These cause an overload state in the IGP to trigger the traffic reroute by setting the overload bit in IS-IS or setting the metric to maximum in OSPF. When PIM uses IS-IS or OSPF to find out the upstream router, a next-hop change in the IS-IS or OSPF will cause PIM to join the new path and prune the old path, which effectively also reroutes the multicast traffic downstream as well as the unicast traffic.
When the problem is resolved, and the required compliment of SFMs become active in the router, the overload condition is cleared, which will cause the traffic to be routed back to the router.
The conditions to set overload are:
- 7750 SR-12/SR-7/SR-c12 and 7450 ESS-12/ESS-7/ESS-6 platforms: protocol sets overload if one of the SF/CPMs fails
- 7750 SR-12e and 7950 XRS platforms: protocol sets overload if two SFMs fail (two SFMs belonging to different SFM pairs on the XRS-40)
2.12. Service Management Tasks
This section describes IP router service management tasks:
2.12.1. Changing the System Name
The system command sets the name of the device and is used in the prompt string. Only one system name can be configured. If multiple system names are configured, the last one configured will overwrite the previous entry.
To change the system name:
The following example shows the configuration to change the system name:
The following example shows the system name change:
2.12.2. Modifying Interface Parameters
Starting at the config>router level, navigate down to the router interface context.
To modify an IP address:
To modify a port:
The following example shows the interface configuration:
2.12.3. Removing a Key Group from a Router Interface
Use the following CLI syntax to remove a key group from a router interface:
The following example displays a key group removed from a router interface:
The following example shows that the key group configuration has been removed from a router interface.
2.12.4. Changing the Key Group for a Router Interface
The following CLI syntax changes the key group on a router interface. In the example below, the inbound and outbound key groups are changed from key group 6 to key group 8.
The following example shows that the key group configuration has been changed for the router interface.
2.12.5. Deleting a Logical IP Interface
The no form of the interface command typically removes the entry, but all entity associations must be shut down and/or deleted before an interface can be deleted.
- Before an IP interface can be deleted, it must first be administratively disabled with the shutdown command.
- After the interface has been shut down, it can then be deleted with the no interface command.