R0106-HP MSR Router Series Layer 3 - IP Services Configuration Guide(V7)

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Displaying the adjacency table
In this chapter, "MSR2000" refers to MSR2003. "MSR3000" collectively refers to MSR3012, MSR3024,
MSR3044, MSR3064. "MSR4000" collectively refers to MSR4060 and MSR4080.
The adjacency table stores information about directly connected neighbors for IP forwarding. The
neighbor information in the adjacency table 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 contains the neighbor network layer address
(next hop), output interface, link layer protocol type, and link layer address (PVC for ATM, unavailable
for PPP).
When forwarding an IP packet, the device does the following:
• 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 that is required for forwarding the packet.
NOTE:
Ethernet neighbor information and non-Ethernet nei
g
hbor information are stored and mana
g
ed to
g
ether.
The following table shows the items contained in an adjacency table output:
Item Descri
p
tion
IP address
IP address of the next hop in FIB table for packet forwarding. 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. If the routing interface
is physical, the routing interface and physical interface are the same. If the
routing interface is logical, the routing interface and physical interface are
different.
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. P2P indicates
a point-to-point link, and NBMA indicates a non-broadcast multi-access link.
Link head information(IP) Link layer header for IP forwarding.
Link head information(IPv6) Link layer header for IPv6 forwarding.
Slot ID of the slot that holds the card.
Virtual circuit information
Information about the virtual circuit, such as PVC or DLCI. If the entry has no
virtual circuit, this field displays N/A.