The growing demand for IP addresses has put a severe strain on the classful model. Most companies requesting Class B addresses have estimated that a Class B address would best accommodate their requirements because of the balance between the number of networks and the number of hosts. A Class A was overkill, with more than 16 million hosts, and a Class C had too few hosts per network. By 1991, it was becoming obvious that the Class B consumption was not slowing and actions ..
Better Protection of Enable and Username Passwords
The password required by the enable command can be defined by either the enable password pw command or the enable secret pw command. If both are configured, the enable exec command only accepts the password defined in the enable secret command. The password in the enable password command follows the same encryption rules as login passwords, only being encrypted if the service password-encryption command is configured. However, the enable secret password is not affected by ser..
To modify U.S. routers, configure R2, R3, and R4 as the backbone routers because they are connected to the backbone routers defined in Europe. At this point, it is a good idea to move one of the three U.S. circuits from R1 to R13, so that it has a connection to the United States. If R1 goes down, there is only one connection to the United States left, via R9. The link between R9 and R2 is slow, so losing R1 means that all high-speed links to the United States ar..
Although two OSPF routers can form an adjacency (that is, become neighbors) through the exchange of Hello packets, the following parameters in the Hello packets must match: ■ Hello timer: This timer defaults to 10 seconds for broadcast and point-to-point networ types. The default is 30 seconds for nonbroadcast and point-to-multipoint networ types. ■ Dead timer: This timer defaults to 40 seconds for broadcast and point-to-point networ types. The default is 120 seconds fo..
One of the most significant shortcomings of PIM-SM is that within any given multicast network boundaries, there can be only one RP for any multicast group. This has several potential problems including slow convergence after an active RP failure and potentially extra hops required to reach a distant RP. Anycast RP solves these problems. The first RP configuration looks like this: Router-RP1#configure terminal Enter configuration commands, one per line. End with CNTL..
