IP Routing Overview window 191Models 2616RC, 3096RC & 3196RC Admin Reference Guide 12 • IP (IP, TCP, UDP, & ICMP)Mask (genRouteMask)Indicates the mask to be logical-ANDed with the destination address before being compared to the value in theipRouteDest field. For those systems that do not support arbitrary subnet masks, an agent constructs the valueof the ipRouteMask by determining whether the value of the correspondent ipRouteDest field belongs to aClass A, B, or C network, and then using the appropriate mask from table 4.Gateway (genRouteGateway)Specifies the IP address to which the packets should be forwarded.Cost (genRouteCost)This is the cost of the route as defined by RIP standards. Cost is sometimes considered to be number of hops.A cost of 16 is considered to be infinite. A cost can be given to user-entered routes so their preference in rela-tion to learned routes can be calculated.Interface (genRouteIfIndex)The index value that identifies the local interface through which the next hop of this route should be reached.The interface identified by a particular value of this index is the same interface as identified by the same valueof ifIndex. This may be zero in the case that the route is not active or no interface could be found which hasaccess to the gateway.Protocol (genRouteProto)The mechanism by which this route was learned is defined by protocol. The parameters are:• unknown(0)• local(1)—Added by O/S to support an interface• user(2)—Added through row creation in this MIB• rip(4)—Added by reception of a RIP packet• icmp(5)—Added by reception of an ICMP packet• radius(6)—Provided in a RADIUS response packetState (RouteState)• invalid(1)—This setting deletes the route.• active(2)—A valid route is in use.• nopath(3)—No route is available to the specified gateway. The gateway is not known to local networks.Table 4. MasksMask Network255.0.0.0 class-A255.255.0.0 class-B255.255.255.0 class-C
