3.20 - Implement IPv6 neighbor discovery Flashcards
What are the five ICMPv6 messages used by the Neighbor Discovery Protocol?
Router Advertisement (RA)Router Solicitation (RS)Neighbor Solicitation (NS)Neighbor Advertisement (NA)Redirect
What is the purpose of the M and O flags in the RA?
The are used for address autoconfiguration. M for Managed access and O for other stateful
What is the purpose of the Reachable Time field of the RA?
Specifies the time in that a node should assume a neighbor is reachable after the neighbor confirms it reachability (in ms)
What is the purpose of the Retransmit Timer field in the RA?
specifies the minimum time between retransmitted Neighbor Solicitation messages (in ms)
What is indicated if the Router Lifetime field in the RA is set to 0?
Indicates that the originating router should not be added to the host’s default router list.
What is the purpose and effect of the S flag in the NA?
Solicited flag, is set when the NA is in response to an NS.
What is the difference between stateful and stateless address autoconfiguration?
Stateful address autoconfiguration relies on DHCPv6 for address allocation. Stateless address autoconfiguration usues RA’s to determine a prefix of a larger scope to determine host’s address
When a device acquires a unicast IPv6 address it must perform Duplicate Address Detection, with one exception. What is that exception?
Never performed on an anycast address
What does the prefix FF02:0:0:0:0:1:FF00::/104 signify?
Solicited node multicast adddresses. Prepended to the last 24 bits of an address being solicited.
What does IPv6 use in place of ARP and an ARP cache?
NDP Neighbor Address function
What does an Incomplete state of an entry in the neighbor cache signify?
Neighbor Address resolution is in progress
What does a Probe state of an entry in the neighbor cache signify?
An NS has been sent to verify two-way reachability of a stale entry but the NA has not been received.
What two ways does Neighbor Unreachability Detection use to verify two-way reachability of a neighbor?
Either by “hints” from an upper level protocol or by actively probing the neighbor with an NS.
What is the purpose and effect of the R flag in the NA?
Indicates the originator is a router in an NA packet
What is the purpose and effect of the O flag in the NA?
Indicates that the information contained in the NA should override any existing neighbor cache entry and update the cached link-layer address.
What is the command to enable the sending of RAs on ethernet and FDDI interfaces?
ipv6 unicast-routing
What is the command to change the IPv6 RA interval?
ipv6 nd ra-interval
What is the command to change the RA Router Lifetime on a cisco router?
ipv6 nd ra-lifetime
What is the default RA interval on a Cisco router?
200 seconds
What is the default value of RA Router Lifetime on a cisco router?
1800 seconds
What is the default reachable time on Cisco router?
0 (unspecified)
How do you set the reachable time of an RA?
ipv6 nd reachable-time
How do you set the retransmit timer of an RA?
ipv6 nd ns-interval
What is the default of the RA retransmit timer on a Cisco?
0 ms
What is the command to set the M flag for RA on a Cisco router?
ipv6 nd managed-config-flag
What is the command to set the O flag for RA in a Cisco router?
ipv6 nd other-config-flag
