EIGRP is designed to work in very large networks. However, EIGRP is design-sensitive. Scaling a network is a major concern in organizations. New demands are constantly driving the networks to use applications that require more bandwidth and less delay; at the same time networks are becoming larger and more complex. Mergers and acquisitions, for instance, do nothing for good design. The factors that can affect the scaling of EIGRP include: • The amount of..
OSPF is an Interior Gateway Protocol (IGP), whereby each router belonging to a single area maintains an identical database. The routing table is constructed from the information in this database by running a Shortest Path First algorithm. The route is installed in the table by first resolving the least-cost route to the destination. OSPF routes packets are based solely on the IP destination, so there is no room for source-based routing. OSPF also uses IP multicast for updates..
When mainframe computers dominated the industry, user terminals attached either directly to ports on the computer or to a controller that gave the appearance of a direct connection. Each wire connection was dedicated to an individual terminal. Users entered data, and the terminal immediately transmitted signals to the host. Performance was driven by the horsepower in the hosts. If the host became overworked, users experienced delays in responses. Note, though, that the connec..
Creating an Encrypted Router-to-Router VPN in a GRE Tunnel
There are several steps to these configurations, but they are the same on both routers. The first step is to create an appropriate key exchange policy using ISAKMP. The following set of commands defines the policy with priority 10. When ISAKMP negotiates the security association (SA) parameters, it starts with the lowest priority and goes to the highest. The highest possible priority value is 10,000: Router1(config)#crypto isakmp policy 10 Router1(config-isakmp)#encr aes 256..
Extended IP access-lists can also filter based on application information, such as protocol and port numbers: Router1#configure terminalEnter configuration commands, one per line. End with CNTL/Z.Router1(config)#access-list 151 permit tcp any any eq wwwRouter1(config)#access-list 151 deny tcp any any gt 1023Router1(config)#access-list 151 permit icmp any anyRouter1(config)#access-list 151 permit udp any any eq ntpRouter1(config)#access-list 151 deny ip any anyRouter1(co..
