This decision step simply prevents BGP from making the poor choice of accepting a BGP route as best, even though that router cannot possibly forward packets to the next-hop router. Routing policies do not typically attempt to change a NEXT_HOP address to impact a routing choice. However, the NEXT_HOP can be changed by using either the neighbor neighbor-id nexthop- self command (the default for eBGP peers) or the neighbor neighbor-id next-hopunchanged command (the default for ..
Label Imposition at the Network Edge
Label imposition has been described already as the act of prepending a label to a packet as it enters the MPLS domain. This is an edge function, which means that packets are labeled before they are forwarded to the MPLS domain. To perform this function, an Edge-LSR needs to understand where the packet is headed and which label, or stack of labels, it should assign to the packet. In conventional Layer 3 IP forwarding, each hop in the network performs a lookup in the IP forwar..
Introduction to the QoS Toolset
A fair amount of literature exists on QoS concepts, technologies, and features. The purpose of this book is not to reiterate in depth how these tools work, but rather to show how these tools interact with each other and what combination of tools can be used to achieve the overall design objectives of a network. However, to lay the context for the designs set forth in this book, a brief overview of the toolset follows. Generally, QoS tools fall into the following categories: ..
Starting with IOS Version 12.4(2)T, Cisco introduced support for stronger encryption capabilities. To enable 3DES use the following command: Router1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router1(config)#snmp-server user wbrejniak ORAROV3 v3 auth md5 authpass priv 3des privpass Router1(config)#end &n..
Adaptive shaping to ForeSight allows a Cisco router to respond to ForeSight messages and to react to network congestion by enabling VC-level traffic shaping and rate limiting in a timely manner. Adaptive shaping to ForeSight is a component of Frame Relay Traffic Shaping. On Cisco switches, router ForeSight is a network traffic control software that allows the Frame Relay switches to extend ForeSight messages over a User-to-Network (UNI) interface and passes the BECN bit for V..
