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Category: Cisco
- BGP regexp
Regular Expression:
show ip bgp regexp [AS]$ - list all network paths with that AS show ip bgp regexp _AS_ - match any route going through AS show ip bgp regexp _AS AS_ - match any route passed through AS and AS show ip bgp regexp _AS$ - match only routes originated in this AS
- Cisco Tacacs configuration
aaa new-model aaa authentication login default group tacacs+ enable aaa accounting exec default start-stop group tacacs+ aaa accounting commands 15 default stop-only group tacacs+ aaa accounting network default start-stop group tacacs+ aaa accounting connection default start-stop group tacacs+ aaa accounting system default start-stop group tacacs+ tacacs-server host 10.100.100.100 timeout 5 no tacacs-server directed-request tacacs-server key 7 key
- Route servers
Route servers:
colt = telnet route-server.colt.net cerf = telnet route-server.cerf.net att = telnet route-server.cbbtier3.att.net att1 = telnet route-server.ip.att.net bbn = telnet ner-routes.bbnplanet.net oregon = telnet route-views.oregon-ix.net exodus = telnet route-server.exodus.net as elnet = telnet route-server.as5388.net gblx.net = telnet 206.132.67.9 tiscalli = telnet route-server.ip.tiscali.net belwue = telnet route-server.belwue.de telus = telnet route-views.on.bb.telus.com telus = telnet route-views.ab.bb.telus.com is = telnet public-route-server.is.co.za opentr = telnet route-server.opentransit.net JUNOS 9.0R3.6 GT = telnet route-server.gt.ca He = telnet route-server.he.net Manilla = telnet route-server.manilaix.net.ph Allstream = telnet route-server.central.allstream.com AllstreamE = telnet route-server.east.allstream.com AlstreamW = telnet route-server.west.allstream.com TwTel = telnet route-server.twtelecom.net GBLXe = telnet route-server.eu.gblx.net EUNet = telnet route-server.as6667.net Sunrise = telnet routeserver.sunrise.ch Host = telnet route-server.host.net Optus = telnet route-views.optus.net.au Washingt = telnet route-views3.routeviews.org (Juniper)
- Internetwork
Internetwork
The Frontier Optronics Network now encompasses 11 hub cities. The northern route connects Los Angeles, San Francisco, Kansas City, Cleveland, and New York City at OC-48c or 2.5 Gbps speeds. A second backbone, through the South, connects Los Angeles, San Diego, Dallas, Atlanta, Washington D.C., and New York City—also at OC-48c. The two routes are joined together in a ring architecture, giving the backbone extended reliability and failover protection—a clear advantage over linear route networks (See Figure 1).
Optical Internet Benefits: Scalability and Simplicity
The hierarchical design of IP hubs in the Frontier Optronics Network provides Frontier with a robust and scalable infrastructure. At the highest level, redundant wide-area routers (WR1 and WR2) connect to the IP backbone at OC-48 speeds. At the middle layer, core routers (CR1 and CR2) connect lower layers to the WR routers at OC-12 speeds. At the lowest layer, an assortment of routers deliver specialized services: access routers (AR1) aggregate T1, T3 and OC-3 traffic; border routers (BR1) provide peering connections with other Internet providers; hosting routers (HR1) provide hosting services for web content; and dial routers (DR1) handle lower-speed customer access.
- Bgp dampening
Cisco BGP dampening
Description:
When a route fails, a routing update is sent to withdraw the route from the network’s routing tables. When the route is re-enabled, the change in availability is also advertised. A route that continually fails and returns requires a great deal of network traffic to update the network about the route’s status.Route dampening enables you to identify routes that repeatedly fail and return. If route dampening is enabled, an unstable route accumulates penalties each time the route fails and returns. If the accumulated penalties exceed a threshold, the route is no longer advertised. This is route suppression. Routes that have been suppressed are re-entered into the routing table only when the amount of their penalty falls below a threshold.
A penalty of 1000 is assessed each time the route fails. When the penalties reach a predefined threshold (suppress-value), the router stops advertising the route.
Once a route is assessed a penalty, the penalty is decreased by half each time a predefined amount of time elapses (half-life-time). When the accumulated penalties fall below a predefined threshold (reuse-value), the route is unsuppressed and added back into the BGP routing table.
No route is suppressed indefinitely. Maximum-suppress-time defines the maximum time a route can be suppressed before it is re-advertised
Use the bgp dampening command with arguments to override the defaults. If any argument is used, all the arguments must be defined.
Use the route-map keyword to associate a route-map to the dampening functionality. Only matching routes will be dampened according to the supplied parameters.
Use the no bgp dampening command to disable route dampening.
router(config)#bgp dampening router(config)#bgp dampening 20 1800 8000 50
The following example enables route dampening and sets the half-life-time to 20 minutes, the reuse-value to 1800, the suppress-value to 8000, and the maximum-suppress-time to 50 minutes.
[[Category:Cisco]]