Distribution/Regional Network Design

The role of the regional network is to route intra- and inter-regional traffic. The regional network generally is comprised of a DC as the hub and a number of access POPs as the spokes. Usually, two redundant routers in each regional network will connect to the backbone.   DCs may also provide services such as Web-caching, DNS, network management, and e-mail hosting. In some cases, the latter functionality may be extended into major POPs.   Placement o..

Using SNMP to Extract Inventory Information from a List of Routers

The following Perl script extracts important router informationsuch as router name, physical location, contact name, and serial number from a list of routersand creates a report of this information. The script is intended to be run manually, and no arguments are required or expected. Here's some example output: Freebsd% ./inventory.pl   Router             Location        ..

View Dial Backup Status

Here are some useful commands for looking at the status of a dial backup link. For dial backup that uses the floating static or dialer watch type configurations, you can use the show dialer command: Router1#show dialer For dial configurations that use the backup interface configuration, you can use the show backup command: Router1#show backup And, for backup configurations that use ISDN, you can get some additional information from the show isdn status, show isdn active, ..

Disabling OSPF on Certain Interfaces

The passive-interface configuration command effectively disables OSPF on an interface by preventing it from forming OSPF adjacencies: Router3#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router3(config)#router ospf 44 Router3(config-router)#network 0.0.0.0 255.255.255.255 area 100 Router3(config-router)#passive-interface Ethernet0 Router3(config-router)#exit Router3(config)#end Router3# A useful variant of this command allows you to..

Dynamically Allocating Client IP Addresses via DHCP

The following set of configuration commands allows the router to dynamically allocate IP addresses to client workstations: Router1#configure terminal Enter configuration commands, one per line.  End with CNTL/Z. Router1(config)#service dhcp Router1(config)#ip dhcp pool 172.25.1.0/24 Router1(dhcp-config)#network 172.25.1.0 255.255.255.0 Router1(dhcp-config)#default-router 172.25.1.1 Router1(dhcp-config)#exit Router1(config)#ip dhcp excluded-address 172.25.1.1 172..