AUTONOMOUS SYSTEM - Cisco Learning Network DOES ALL THE ROUTERS UNDER THE SAME AUTONOMOUS SYSTEM RUN THE SAME ROUTING PROTOCOL? FOR EX IF 10 ROUTERS ARE UNDER THE SAME AS, WILL THEY ALL RUN OSPF OR EIGRP OR RIP?
Cisco Learning Network OSPF is an IGP(Interior Gateway Protocol) used inside an AS(Autonomous System) Each AS has its own IGP OSPF uses an hierarchical structure that divides the AS in areas,Area 0 is the backbone and MUST always exists, all other areas connect to area 0
ABR vs ASBR - Cisco Learning Network An Autonomous System Boundary Router (ASBR) is a router that is running multiple protocols and serves as a gateway to routers outside the OSPF domain and those operating with different protocols The ASBR is able to import and translate different protocol routes into OSPF through a process known as redistribution
EIGRP Address family - Cisco Learning Network Each named mode configuration can have multiple address families and autonomous system number combinations In the named mode, you can have similar configurations across IPv4 and IPv6 We recommend that you upgrade to EIGRP named mode because all new features, such as Wide Metrics, IPv6 VRF Lite, and EIGRP Route Tag Enhancements, are available
What should be done to set up communication between 2 ASN in Eigrp If multiple EIGRP autonomous systems are used with multiple points of mutual redistribution, it can cause discrepancies in the EIGRP topology table if correct filtering is not performed at the redistribution points If possible, Cisco recommends you configure only one EIGRP autonomous system in any single autonomous system
Two EIGRP AS number and two equal paths to the same destination Therefore when a router learns two EIGRP routes with two equal paths metric , the route learned through the lower Autonomous System (AS) number is installed in the routing table Let's decrease the bandwidth of the preferred path R3: R1(config) #int fa0 1 R1(config-if) #band R1(config-if) #bandwidth? <1-10000000> Bandwidth in kilobits
OSPF LSA Types - Cisco Learning Network LSA Type 5: Autonomous system external LSA; LSA Type 6: Multicast OSPF LSA; LSA Type 7: Not-so-stubby area LSA; LSA Type 8: External attribute LSA for BGP Like Steven said, these are just headings for each LSA type, if you want to dig deeper you issue commands like: show ip ospf data summary 192 168 1 0
BGP Next-Hop self - Cisco Learning Network BGP only cares about paths between Autonomous Systems It ensures loop-free paths between Autonomous Systems It relies on IGP to provide loop-free transit within each Autonomous System To do this, BGP needs to make sure that the IGP is choosing the same exit point This means BGP views the entire AS as a giant router