Filtering BGP Updates by Matching the AS_PATH PA
To filter routes by matching the AS_PATH PA, Cisco IOS uses AS_PATH filters. The overall configuration structure is very similar to BGP distribute lists and prefix lists, with the matching logic specified in a list, and the logic being applied with a neighbor command. The main two steps are as follows: 1. Configure the AS_PATH filter using the ip as-path access-list number {permit | deny} regex command. 2. Enable the AS_PATH filter using the neighbor neighbor-id filter-lis..
Integrated Services Digital Network (ISDN) is used by telephone companies to carry digitized voice and data over the existing telephone system. ISDN has emerged as one of the leading technologies for telecommuting and remote office connection into the corporate headquarters. On the seven layer model, ISDN operates at the physical, data link, and network layers. ISDN basic rate interface (BRI) provides two barrier channels (commonly referred as B channels). Each of these B ch..
NBAR classifies packets that are normally difficult to classify. For instance, some applications use dynamic port numbers, so a statically configured match command, matching a particular UDP or TCP port number, simply could not classify the traffic. NBAR can look past the UDP and TCP header, and refer to the host name, URL, or MIME type in HTTP requests. (This deeper examination of the packet contents is sometimes called deep packet inspection.) NBAR can also look past the TC..
To enable password encryption on a router, use the service password-encryption configuration command: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#enable password oreilly Router1(config)#line vty 0 4 Router1(config-line)#password cookbook Router1(config-line)#line con 0 Router1(config-line)#password cookbook Router1(config-line)#line aux 0 Router1(config-line)#password cookbook Router1(config-line)#exit Router1..
unneling IPv6 Through an Existing IPv4 Network
The easiest way to pass IPv6 traffic through a section of IPv4 network that doesn't offer native IPv6 support is to create a simple GRE tunnel: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#interface Loopback1 Router1(config-if)#ip address 10.15.1.11 255.255.255.255 Router1(config-if)#exit Router1(config)#interface Tunnel1 Router1(config-if)#ipv6 address BBBB:1::1/126 Router1(config-if)#ipv6 rip RIP_PROC ..
