The abilities to control which devices get addresses and track the address assignments for auditing purposes are important issues that can be accomplished using DHCPv6. Ironically, privacy is another reason that DHCPv6 could be a good idea. Normally IPv6 addresses contain the MAC address, a unique ID that can be linked back to a specific system. DHCPv6 could be used to break the link between the MAC address and the Layer 3 address. Stateless DHCPv6 is a m..
When a router receives a CSNP from a neighbor, and it notices that the CSNP is missing part of the database, the router sends a partial sequence number PDU packet (PSNP) to request a newer copy of the LSP. This is similar to the OSPF link-state request packet. The PSNP also acknowledges the receipt of the CSNP. PSNP describes the LSP by its header, just like a CSNP. Unlike the CSNP, however, the PSNP holds information only about the requested LSP, not about all ..
Summary Link-State Types 3 and 4
Summary type 3 propagates information about a network outside its own area. Many network administrators assume that summary LSA generates information outside the area by summarizing routes at the natural network boundary, although this has been proven untrue. For example, a summary LSA will not summarize all subnets of a major network 131.108.0.0 in a /16 route. Summary in OSPF does not mean that summarize occurs at the classful network boundary. In this case, s..
The richness of the Cisco QoS toolset allows for a myriad of QoS design and deployment options. However, a few succinct design principles can help simplify strategic QoS designs and lead to an expedited, cohesive, and holistic end-to-end deployment. Some of these design principles are summarized here; others, which are LAN-, WAN- or VPN-specific, are covered in detail in their respective design chapters. General QoS Design Principles A good place to begin is to decide which c..
Disabling Link Up/Down Traps per Interface
To disable SNMP link-status change traps for a particular interface, use the following configuration command: Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#interface Serial0/0 Router(config-if)#no snmp trap link-status Router(config-if)#exit Router(config)#end Router# By default, the router forwards SNMP link up or down traps whenever an interface changes states. Normally, you want to receive traps when an inter..
