Displaying the adjacency table
The adjacency table stores information about directly connected neighbors for IP forwarding. The neighbor information in this chapter refers to non-Ethernet neighbor information.
This table is not user configurable. The neighbor information is generated, updated, and deleted by link layer protocols through negotiation (such as PPP dynamic negotiation) or through manual configuration (such as ATM static configuration). An adjacency entry includes the following information:
Neighbor network layer address (next hop).
Output interface.
Link layer protocol type.
Link layer address. This field displays PVC for ATM, and it is not available for PPP.
When forwarding an IP packet, the device performs the following tasks:
Searches the FIB to find the output interface and next hop.
Uses the output interface and next hop address to search the adjacency table for link layer forwarding information.
NOTE: Ethernet and non-Ethernet neighbor information are stored and managed together. | ||
The following table shows the items in an adjacency table output:
Item | Description |
---|---|
IP address | IP address of the next hop in the FIB table. This address is used for adjacency table lookup. |
IPv6 address | IPv6 address of the next hop in the FIB table. This address is used for adjacency table lookup. |
Routing interface | Output interface in the matching route entry. This interface is used for adjacency table lookup, and it can be logical or physical. |
Physical interface | Output physical interface that sends matching packets.
|
Logical interface | Logical interface for sending packets, such as a virtual-Ethernet interface for ATM, or a Virtual-Template interface for MP. |
Service type | Link layer protocol type, such as PPP or HDLC. |
Action type | Action to be taken on the matching packet: Forwarding or Drop. |
Link media type | Related to the link layer protocol used by the routing interface.
|
Link head information(IP) | Link layer header for IP forwarding. |
Link head information(IPv6) | Link layer header for IPv6 forwarding. |
Link head information(MPLS) | Link layer header for MPLS forwarding. |
To display adjacency table entries, use one of the following commands in any view:
Task | Command |
---|---|
Display IPv4 adjacency table information. | display adjacent-table { all | physical-interface interface-type interface-number | routing-interface interface-type interface-number | slot slot-number } [ count | verbose ] |
Display IPv6 adjacency table information. | display ipv6 adjacent-table { all | physical-interface interface-type interface-number | routing-interface interface-type interface-number | slot slot-number } [ count | verbose ] |