Configuring The Default Route - 3Com 3C13636 Configuration Manual

3Com Router 3000 Ethernet Family
Configuration Guide
1) VPN instance name
2) IP address and mask
An IP address is in dotted decimal format. As the "1" in a 32-bit mask is required to be
consecutive, a mask can be represented either by dotted decimal notation or by mask
length (namely the bits of "1" in a mask).
3) Transmitting interface or next-hop address
To configure a static route, you can either specify the interface-name of a sending
interface or the gateway-address of a next-hop address. It depends on specific
situation.
Virtually, it is necessary to specify the next-hop addresses of all route entries. During
packet forwarding over IP, a router first finds matched route from the routing table
according to the destination address of a packet. Only when the next-hop is specified,
can the link layer finds corresponding link layer address via the next-hop IP address
and forward the packet according to the address.
A sending interface can be specified in the following cases:
For a point-to-point interface, when a sending interface is specified, it implicates
that the next-hop address is also specified. In this case, the peer interface address
connected with the interface is regarded as the next-hop address of the route. For
example, in the case that SERIAL interface is encapsulated with PPP, the peer IP
address can be obtained via PPP negotiation. It is unnecessary to specify the
next-hop address but specifying the sending interface.
For an NBMA interface (such as an ATM interface), which supports
point-to-multipoint, it is necessary to create reroute at link layer, namely the
mapping from an IP address to a link layer address, besides configuring IP routes.
To configure static route in this case, you should configure the next-hop IP address
rather than specify the sending interface.
4) Precedence
The preference can be configured differently by flexibly applying route management
policies.
5) Other parameters
The attributes reject and blackhole respectively indicate the unreachable route and the
blackhole route. The public attribute specifies that a public address is specified. The tag
attribute specifies the tag of a static route for a routing policy. The description attribute
describes the static route.

2.2.2 Configuring the Default Route

Perform the following configuration in system view.
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Chapter 2 Static Route Configuration