The fundamental problem with EGP is its inability to detect routing loops. Because there is an upper boundary on the distance EGP uses (255), you might be tempted to say that counting to infinity is at least a rudimentary loop-detection mechanism. It is, but the high limit combined with the typical Poll interval makes counting to infinity useless. Given a default Poll interval of 180 seconds, EGP peers could take almost 13 hours to count to infinity. As a result, EGP must be..
Point-to-Point Configuration over NBMA
The point-to-point configuration requires an IP subnet for every link. This is the recommended way to run IS-IS over NBMA and the only way to do it on anything less than a full mesh. The configuration is simpler, because the link is point-to-point and there is no need to configure frame-relay map commands. As shown in Example 10-6, it is only necessary to create subinterfaces, configure those interfaces as point-to-point, start Frame Relay, and define the DLCI..
Overview of the BGP as MPLS Control Plane
MPLS architecture allows multiple protocols for distributing label information between LSRs.[1] MPLS label-distribution protocols are based on either extending the capabilities of existing protocols, as in the case of BGP and RSVP-TE, or explicitly defining new protocols for this purpose, as in the case of LDP. This chapter mainly focuses on the role of BGP as a label-distribution protocol. BGP and MPLS Interrelationship As discussed earlier, MPLS-based L3VPNs use LDP or RS..
Certificate Enrollment Protocol
CEP is a protocol jointly developed by Cisco and VeriSign, Inc. CEP is an early implementation of Certificate Request Syntax (CRS), a proposed standard to the IETF. CEP specifies how a device communicates with the CA, how to retrieve the CA's public key, and how to enroll a device with the CA. CEP uses Public Key Cryptography Standards (PKCS). CEP uses HTTP as a transport mechanism and uses the same TCP port (80) used by HTTP. Note You can find more details on CEP at http:..
So far in this section, the database exchange process has focused on exchanging the database between neighbors. However, LSAs need to be flooded throughout an area. To do so, when a router learns new LSAs from one neighbor, that router then knows that its other neighbors in that same area may not know of that LSA. Similarly, when an LSA changes, for example, when an interface changes state, a router may learn the same old LSA but with a new sequence number, and again need to ..
