Multicast Listener Discovery Protocol
RFC 2710 defines specifications for the Multicast Listener Discovery (MLD) protocol. MLD is derived from IGMPv2 and is designed for IPv6. The operation of MLD is similar to IGMPv2. The major differences between IGMPv2 and MLD are as follows: ■ All the multicast devices on a subnet use a special IPv6 link-local address as their source address in their communication to other multicast devices. The use of the link-local source address prevents the MLD packet from traveling be..
When CB Policing re-marks packets instead of discarding them, the design might call for marking more than one field in a packet. For instance, when transmitting into a Frame Relay cloud, it might be useful to mark both DSCP and FR DE when a packet violates the contract. Marking multiple fields in the same packet with CB Policing is called multi-action policing. The police command uses a slightly different syntax to implement multi-action policing. By omitting the actions fro..
Protecting Cisco IOS from Intrusion
Now that you have a snapshot of modern security concerns, look at Cisco IOS and the configuration commands you can use to deny intruders the ability to harm valuable network resources that are typically connected behind a Cisco router. In particular, this section covers how you can stop DoS attacks. There are, of course, various Cisco IOS vulnerabilities that can only be protected against by new software releases and regular Cisco IOS bulletins and e-mail blasts from Cisco S..
An AP can provide WLAN connectivity to only the clients within its range. The signal range is roughly defined by the AP’s antenna pattern. In an open-air setting, this might be a circular shape surrounding an omnidirectional antenna. At least the pattern will appear as a circle on a floor plan—keep in mind that the pattern is three-dimensional, also affecting floors above and below, in a multilevel building. The AP’s location must be carefully planned so that its range..
Redistributing Static Routes into RIP
The biggest potential problem that you will encounter with redistributing routes into RIPv1 comes from breaking network class boundaries. This version of RIP is classful, so you have to be rather careful about how you distribute routing information from other sources that may be classless. In the example in this recipe, Router1 redistributes a static route for the Class C network 192.168.10.0. But if we tried instead to redistribute a larger range, such as 192.168.12.0/22, RI..
