Policy Routing Based on Traffic Source
Consider the example shown in Figure 8-6. Assume that AS1 was assigned network numbers from two different providers. The 10.10.10.0/24 range was taken from AS3, and the 11.11.11.0/24 range was taken from AS4. AS1 wants to have any traffic originated from its 10.10.10.0/24 networks to be directed toward AS3 and traffic from its 11.11.11.0/24 networks to be directed to AS4, irrespective of the traffic's final destination. AS1 could use policy routing to achieve this requirement..
Dissecting the Component Parts of an IP Address
First, deducing the size of the three parts (classful view) or two parts (classless view) of an IP address is important, because it allows you to analyze information about that subnet and other subnets. Every internetwork requires some number of subnets, and some number of hosts per subnet. Analyzing the format of an existing address, based on the mask or prefix length, allows you to determine whether enough hosts per subnet exist, or whether enough subnets exist to sup..
PIM-SM routers could continue forwarding packets via the PIM-SM two-step process, whereby sources send packets to the RP, and the RP sends them to all other routers using the RPT. However, one of the most fascinating aspects of PIM-SM operations is that each PIM-SM router can build the SPT between itself and the source of a multicast group and take advantage of the most efficient path available from the source to the router. In Figure 20-16, R4 is receiving the group traffi..
Enhanced IGRP and Bandwidth Control
Before continuing with Enhanced IGRP and bandwidth-related commands, you should understand bandwidth control. By default, Enhanced IGRP limits itself to 50 percent of the configured bandwidth. A benefit of controlling Enhanced IGRP usage is that it limits the Enhanced IGRP traffic in case of failure. This makes the rest of the bandwidth available for data traffic. Another advantage is that you avoid losing Enhanced IGRP packets, which could occur when Enhanced IGRP generates ..
Logging Unauthorized SNMP Attempts
Use the following commands to configure your router to log unauthorized SNMP requests: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#access-list 99 permit 172.25.1.0 0.0.0.255 Router(config)#access-list 99 permit host 10.1.1.1 Router(config)#access-list 99 deny any log Router(config)#snmp-server community ORARO ro 99 Router(config)#snmp-server community ORARW rw 99 Router(config)#end Router# If you are concerned ..
