CIDR, Private Addresses, and NAT
The sky was falling in the early 1990s in that the commercialization of the Internet was rapidly depleting the IP Version 4 address space. Also, Internet routers’ routing tables were doubling annually (at least). Without some changes, the incredible growth of the Internet in the 1990s would have been stifled. To solve the problems associated with this rapid growth, several short-term solutions were created, as well as an ultimate long-term solution. The short-term solution..
1245. PPP Security As described in Chapter 17, “Synchronous Serial Links and Protocols,” PPP provides the capability to use PAP and CHAP for authentication, which is particularly useful for dial applications. Chapter 17 used only the default authentication method for CHAP/PAP—namely, the reliance on a locally configured set of username name password password commands. Cisco IOS supports the use of AAA authentication for PPP using the same general set of commands as used..
Making Interface Table Numbers Permanent
To ensure that SNMP interface numbers remain permanent after a router power cycle, use the following command. This is a global command that affects all interfaces: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#snmp-server ifindex persist Router(config)#end Router# You can also fix the SNMP interface number of a single interface as follows: Router#configure terminal Enter configuration commands, one per line. ..
Multicast over Frame Relay or ATM WANs
When using PIM-SM on an nonbroadcast multiple access (NBMA) network, such as a Frame Relay or ATM WAN, you must configure the ip pim nbma-mode interface command: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#ip multicast-routing Router1(config)#interface Serial0/0 Router1(config-if)#encapsulation frame-relay Router1(config-if)#ip pim sparse-mode Router1(config-if)#ip pim nbma-mode Router1(config-if)#end ..
End-to-end VLANs, also called campuswide VLANs, span the entire switch fabric of a network. They are positioned to support maximum flexibility and mobility of end devices. Users can be assigned to VLANs regardless of their physical location. As a user moves around the campus, that user’s VLAN membership stays the same. This means that each VLAN must be made available at the access layer in every switch block. End-to-end VLANs should group users according to common req..
