Multiprotocol Label Switching Introduction
Multiprotocol Label Switching (MPLS) is an emerging technology that aims to address many of the existing issues associated with packet forwarding in today’s Internetworking environment. Members of the IETF community worked extensively to bring a set of standards to market and to evolve the ideas of several vendors and individuals in the area of label switching. The IETF document draft-ietf-mpls-framework contains the framework of this initiative and describes the primary go..
KEEPALIVE messages are comprised only of the 19-byte BGP message header shown in Figure 11-3. These are exchanged whenever an update-free period exceeds the holdtime negotiated in the OPEN message exchange. A KEEPALIVE is also sent to acknowledge the OPEN message before moving from the OPEN_SENT to ESTABLISHED session state. If the holdtime is zero, KEEPALIVE messages are not sent, except to acknowledge an OPEN. TIP The minimum keepalive period is ..
IP routing is integrated into IS-IS via carrying IP reachability information in LSPs. All Internet Protocol (IP) networks are considered externals, and they always end up as leaf nodes in the shortest path tree when IS-IS runs SPF. This means that changes in IP reachability alone result in only a partial SPF run (partial route calculation, or PRC). The routers in the tree need to calculate only the parts of the tree in which the leaf node for that destination network resides..
Enabling and Disabling NTP Per Interface
Depending on the level of access control required, you can use the ntp disable command to prevent the router from providing NTP services on a particular interface: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#interface Serial0/1 Router(config-if)#ntp disable Router(config-if)#end Router# You can also prevent the router from providing NTP services on an individual interface with access control lists: Router#con..
Next, you need to choose the VTP mode for the new switch. The three VTP modes of operation and their guidelines for use are as follows: ■ Server mode—Server mode can be used on any switch in a management domain, even if other server and client switches are in use. This mode provides some redundancy in case of a server failure in the domain. Each VTP management domain should have at least one server. The first server defined in a network also defines the management domain..
