Manual Summaries and the AS_PATH Path Attribute
As covered in the last several pages, a router can add entries to its BGP table using the network command and route redistribution. Additionally, BGP can use manual route summarization to advertise summary routes to neighboring routers, causing the neighboring routers to learn additional BGP routes. BGP manual summarization with the aggregate-address command differs significantly from using the auto-summary command. It can summarize based on any routes in the BGP table, creat..
The SNMPv1 and SNMPv2 protocol messages (RFC 3416) define how a manager and agent, or even two managers, can communicate information. For instance, a manager can use three different messages to get MIB variable data from agents, with an SNMP Response message returned by the agent to the manager supplying the MIB data. SNMP uses UDP exclusively for transport, using the SNMP Response message to both acknowledge receipt of other protocol messages and supply SNMP information. Ta..
If noise at the radio card is high, the radio card will have difficulty recovering the signal, which results in bits errors and retransmissions. An important signal measurement is the signal-to-noise ratio (SNR). The SNR (in dB) at a particular point in the network is simply the signal power (in dBm) minus the noise power (in dBm). A signal power of –65 dBm and noise power of –90 dBm yields an SNR of 25 dB. The noise power is anything other than signals corresponding to t..
As previously mentioned, the two primary components of forwarding hardware are forwarding logic and backplane. A switch’s backplane, however, is rarely the cause of a switch performance issue, because most Cisco Catalyst switches have high-capacity backplanes. However, it is conceivable that in a modular switch chassis, the backplane will not have the throughput to support a fully populated modular chassis, where each card in the chassis supports the highest combination of ..
Using Policy-Based Routing to Route Based on Application Type
These examples show how to route traffic based on protocol information rather than address information. The first example redirects HTTP packets that originate on any device in the range from 10.15.25.0 to 10.15.25.255. Access list 101 has two lines: Router(config)#access-list 101 deny tcp 10.15.25.0 0.0.0.255 any eq www Router(config)#access-list 101 permit tcp any any eq www The second line matches any TCP packets with any source or destination IP address, and with a desti..
