Much like DSL, cable modems are a fast-growing access technology. Cable modems leverage the high-bandwidth potential of cable TV lines to provide data access services. Because cable modem services were designed to utilize the existing fiber and coaxial cable TV infrastructure, which was optimized to carry one-way broadcasts, available bandwidth is usually very asymmetric in nature. For example, typical services provide capacity close to 2 Mbps downstream (to the subscriber's ..
OSPF has five types of packets used for various reasons. Table 8-1 documents the different OSPF packet types and describes their functionality. Table 8-1. OSPF Packet Types Type Description Functionality 1 Hello To discover neighbors and form DR/BDR relationship and exchange neighbor capabilities. 2 Database description To elect master/slave for the database exchange process and to exchange the LSA ..
Traffic policers measure the traffic rate for data entering or exiting an interface, with the goal of determining if a configured traffic contract has been exceeded. The contract has two components: a traffic rate, configured in bits/second, and a burst size, configured as a number of bytes. If the traffic is within the contract, all packets are considered to have conformed to the contract. However, if the rate or burst exceeds the contract, then some packets are considered..
RSVP-TE Graceful Restart Operation
This section describes the RSVP-TE GR operation for a restarting midpoint LSR. For the sake of brevity, restart behaviors of head-end and tail-end LSRs are omitted because their restart behaviors can be viewed as special cases of the midpoint restart behavior. For the following discussion, see the network topology shown in Figure 9-6. Assume a unidirectional MPLS-TE LSP tunnel originating at the LSR1 (head end) transiting LSR2 (midpoint), and terminating at the LSR3 (tail end..
Before we start this discussion, we need to offer three notes of caution on tuning buffers. First, adjusting your router's buffers is usually not necessary. Second, a poor set of buffer parameters can cause serious performance problems on your router and for traffic passing through the router. Third, if you do find that you need to adjust these parameters, the necessary adjustments will be unique to your network, and perhaps even to each router, so we unfortunately can ..
