As shown in Figure 4 through
Figure 6, each physical P-7500 system provides both a primary and backup virtual router to support system redundancy (as described in
Chapter 9,
“System Redundancy”). Once configured, the primary IP interfaces are active only if the primary virtual router is active (not idle). Likewise, once configured, the backup IP interfaces are active only if the backup virtual router is locally active (not idle). However, unless you are configuring the P-7500 system for redundant operation, configuring the backup virtual router on a P-7500 system is optional since for non-redundant system operation the primary virtual router is always active, and the backup virtual router is always idle.
An IP interface is identified by the physical interface it is associated with and an interface type index, numbered 1 to 3. For example, 1/1/5:1 can identify the primary IP interface on physical interface 1/1/5 (however, 1/1/5:1 can be assigned any of the interface types, that is, primary, backup, or static).
Shutting down the physical interface also disables any associated IP interfaces. However, the IP interfaces can be individually configured to be shutdown separate from their associated physical interface.
The physical interfaces identified as eth1 and eth2 are located on the rear of the P-7500 system. The physical interfaces located on the NAB are identified as 1/1/1 through 1/1/8 for NAB-0801ET, and 1/1/1 through 1/1/2 for NAB-0210EM.
Physical interfaces are configured through the Interface CONFIG CLI commands, and their system configuration can be viewed through the show interface User EXEC command.
An IP interface is created for each LAG configured on the NAB. An IP interface is also created for each ethernet port on the NAB which is not part of a LAG. Each IP interface may have up to three virtual IP addresses associated with it:
From an IP routing standpoint, the primary and backup IP interface states go in and out of activity depending on the configuration and state of the virtual routers. In contrast, the static IP interface states are always active. They are intended as a diagnostic tool to determine IP reachability to the physical ports. Once configured and enabled, the static IP interfaces are always reachable provided link layer connectivity is intact.
Virtual Routing and Forwarding (VRF) is a technology used in networks that allows multiple instances of a routing table to coexist within the same router at the same time. Because the routing instances are independent, the same or overlapping IP addresses can be used without conflicting with each other.
The P-7500 system contains by default two VRF objects called the Management VRF and Message Backbone VRF, respectively. These two VRFs are used by the system to keep management activities, message delivery activities, and routing tables separate.
IP interfaces contained within a VRF are configured through the VRF IP CONFIG CLI commands, and their system configuration can be viewed through the show interface User EXEC command.
Through physical interface eth2 (and associated primary and backup IP interfaces eth2:1 and eth2:2) , the Management VRF handles RV Gateway traffic for the P-7500 system.
The primary and backup virtual routers are served by the Message Backbone VRF. Through the physical interfaces located on the NAB, the Message Backbone VRF handles the client channel traffic (including subject subscriptions) for the virtual routers.