Cisco BGP Configuring BGP on Cisco Routers Set 2

The external routes should be redistributed into an IGP. ✘ The IGP should carry the routes to reach the BGP next-hops and the core subnets within the AS. ✘ The IGP should carry the core subnets within the AS. Then a mutual redistribution between BGP and theIGP should be performed. ✘ The external routes should be redistributed into a Link-State IGP (like OSPF or IS-IS) with filtering to reducethe size of the Link-State database. ✔

A modern transit AS does not rely on redistribution of BGP routes into an IGP. ✘ A modern transit AS does not rely on redistribution of IGP routes into an IGP. ✘ A modern transit AS rely on redistribution of BGP routes into an IGP. ✘ A modern transit AS rely on redistribution of IGP routes into an IGP. ✔ A modern transit AS uses peer group to reduce the BGP configuration complexity. ✔

It limits the number of prefixes that can be sent to neighbor 2.2.2.2 to 1000. ✘ It limits the number of prefixes that can be sent to and received from the 2.2.2.2 neighbor to 1000. ✘ If the number of prefixes sent to the 2.2.2.2 neighbor exceeds 650, the router starts to generate a warningmessage. ✘ If the number of prefixes received from the 2.2.2.2 neighbor exceeds 650, the router starts to generate awarning message. ✔ If the number of prefixes received from the 2.2.2.2 neighbor exceeds 1000, the neighbor relationship to2.2.2.2 will be dropped. ✔

The use of peer group will increase the CPU load of the BGP process. ✘ Peer group is used to reduce the full mesh IBGP requirements for Transit AS. ✘ Peer group is used to sub-divide an AS into multiple sub-ASs to increase scalability. ✘ The use of peer groups allows the router to build BGP update only once for the entire peer group. ✔ IBGP and EBGP neighbors can be assigned to the same peer groups as long as all peer group membershave a common outbound policy. ✔

750 per-flap penalty points which are user configurable. ✘ 1500 per-flap penalty points which are user configurable. ✘ 2000 per-flap penalty points which are user configurable. ✘ 1000 per-flap penalty points which are not user configurable. ✔ 2000 per-flap penalty points which are not user configurable. ✔

When the penalty associated with a route reaches the reuse limit. ✘ When a route is in the history state for longer than the half-time limit. ✘ When the penalty associated with a route reaches the suppress limit. ✘ When a route in the suppressed state for longer then the half-time limit. ✔ When the penalty associated with a route drops below half the reuse limit. ✔

Using the default route. ✘ Using the IGP routes where the external networks are redistributed into the IGP by the edge routers. ✘ Using the EBGP routes where the external networks are redistributed into the IBGP by the edge routers. ✘ Using the IBGP routes, then using recursive lookup based on IGP information to resolve the BGP next-hop. ✔

half-time ✘ reuse-limit ✘ max-suppress ✘ suppress-limit ✔ per-flap-penalty ✔

Route Refresh is not Cisco proprietary. ✘ Route Refresh does not require additional memory. ✘ Route Refresh does not require the BGP session to be taken down. ✘ Route Refresh allows BGP routers to automatically send out new BGP updates. ✔

CE and PE ✘ PE and P ✘ CE and P ✘ P and P ✔ PE and PE ✔