Adding an IP Route
This procedure is used to add an IP route to the database using the ent-ip-rte command.
The ent-ip-rte command uses these parameters.
:loc – The location of the IP card that the IP route will be assigned to.
:dest – The IP address of the remote host or network.
:submask – The subnet mask of the destination IP address.
:gtwy – The IP address of the gateway or router that will send the IP data to its final destination.
There can be a maximum of 64 IP routes assigned to an IP card.
The EAGLE can contain a maximum of 2048 IP routes.
Ethernet Interfaces A and B on the IP card specified by the loc parameter can be used.
The network portion of the IP address value of the gtwy parameter must be the same as the network portion of the IP addresses shown for either the A or B interfaces in the rtrv-ip-card output.
The value of the dest and gtwy parameters cannot be 127.x.x.x (the loopback address), 0.0.0.0, or the IP addresses of the A or B interfaces on the IP card, and cannot be assigned to another IP card.
If the dest parameter value represents a host IP address, the value for the submask parameter must be 255.255.255.255. Otherwise, the submask parameter value is identifies the network/host ID portions that must be entered when the dest parameter value represents a network address.
The submask is applied to the IP address which is being routed to see if it yields a route match. For example, if IP address 192.1.1.2 is being routed and the IP routing table contains these entries.
Table 4-5 Sample IP Routing Table
| IP address | Submask | Gateway |
|---|---|---|
|
191.1.0.0 |
255.255.0.0 |
192.168.110.250 |
|
192.0.0.0 |
255.0.0.0 |
192.168.110.251 |
IP routing occurs as follows:
-
The subnet mask of route 1 (255.255.0.0) is applied to the IP address being routed (192.1.1.2) with the resulting IP address of 192.1.0.0. IP address 192.1.0.0 does not match IP address 191.1.0.0 in the IP routing table, so the next route is chosen.
-
The subnet mask of route 2 (255.0.0.0) is applied to the IP address being routed (192.1.1.2) with the resulting IP address of 192.0.0.0 which matches the second route in the IP routing table, so this route is selected for routing this datagram.
See Table 4-6 for the valid input values for the submask and dest parameter combinations.
Table 4-6 Valid Subnet Mask Parameter Values
| Network Class | IP Network Address Range | Valid Subnet Mask Values |
|---|---|---|
|
A |
1.0.0.0 to 127.0.0.0 |
255.0.0.0 (the default value for a class A IP address) 255.192.0.0 255.224.0.0 255.240.0.0 255.248.0.0 255.252.0.0 255.254.0.0 255.255.128.1 |
|
A+B |
128.1.0.0 to 191.255.0.0 |
255.255.0.0 (the default value for a class B IP address) 255.255.192.0 255.255.224.0 255.255.240.0 255.255.248.0 255.255.252.0 255.255.254.0 255.255.255.128 |
|
A+B+C |
192.0.0.0 to 223.255.255.0 |
255.255.255.0 (the default value for a class C IP address) 255.255.255.192 255.255.255.224 255.255.255.240 255.255.255.248 255.255.255.252 |
If a Class B IP address is specified for the dest parameter of the ent-ip-rte command, the subnet address that results from the dest and submask parameter values cannot be the same as the subnet address that results from the pvn and pvnmask, fcna and fcnamask, or fcnb and fcnbmask parameter values of the chg-netopts command. The pvn and pvnmask, fcna and fcnamask, or fcnb and fcnbmask parameter values can be verified by entering the rtrv-netopts command. Choose dest and submask parameter values for the IP route whose resulting subnet address is not be the same as the subnet address resulting from the pvn and pvnmask parameter values of the chg-netopts command.
Figure 4-10 Adding an IP Route
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