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29 Cards in this Set

  • Front
  • Back
What does IPv6 provide/eliminate?
340 unidecillion address. Eliminates NAT, IPSec built in, no broadcast, multiple ip's per interface, stateless autoconfiguration (no need for DHCP), easy renumbering
How many bits is IP address? What are the syntax tricks for addressing (global prefix configuration features)?
128 bits long - 8 groups of 16 bitsLeading 0's can be eliminated -2001:0008:85a3:0000:0000:0000:0011:7334 -2001:8:85a3:0:0:0:11:7334 successive 0's can be eliminated ○ 2001:0008:85a3:0000:0000:0000:0011:7334 ○ 2001:8:85a3::11:7334
What is the RFC recommendation for network and host bits? Of the network portion how much is prefix and subnet? What is EUI-64?
64 host and 64 network



48 bit global routing prefix and 16 bits for subnet




EUI-64 allows the host portion to be assigned an address. Made up of MAC address. Adds 16 bits in the middle FFFE and flips the 7th bit U/L.

What are the address types?
Unicast, Multicast, Anycast - no broadcast
What are the well known unicast addresses and multicast? What about the Solicited Node Multicast Address?
Global - 2001::/16

Link Local - FE80::/10


Site Local - FEC0::/10 - replaced by unique local which is like private address


unique local - FC00::/7


Multicast - FF00::/8


SNMA - FF02:1::ff[last-24-of-IPV6-address]

IPv6 and IPv6 header size and min MTU

IPv6 40 byte header - 1280 min MTU


IPv4 20 byte header - 576 min MTU


IPv4 Router support fragmentation


IPv6 routers do not

IPv6 has 4 Neighbor Discovery Message Types with thier ICMP codes? What address does it uses for this messages?
Neighbor Advertisement 135, Neighbor Solicitation 136, Router Advertisement, Router Solicitation. It uses the link local addresses.
What are the following message types used for? Neighbor Advertisement, Neighbor Solicitation, Router Advertisement, Router Solicitation.
Duplicate Address Detection - when a device first comes online it will run DAD to check for a unique address.



Neighbor Discovery and Neighbor Advertisement - this replaces ARP. A device will send a NS looking for host and wait for NA.




Stateless Autoconfiguration - Host reads network prefix from RA and uses EUI-64 to make an address without DHCP server.

With DAD and Neighbor Discovery how does addressing work? There is no broadcast address?
For DAD the host will send an NS source with no IP address as source and destination as SNMA for address. At layer 2 it will use 33:33[last-34-bits-of-IPv6-address]. The IPv6 addresses that it is checking is specified as the target address in the NS. If there it will respond to FF02::1/33:33:00:00:00:01 using its link local address. The host will do this for global and link local.



With Neighbor Discovery it will send a NS using my link local/my mac address. Destination will be SNMA/33:33[last-34-bits-of-IPv6-address]. Only the device who has joined this group should get this.

What do devices do during DAD to help stop multicast for being treated like broadcast on the switch?
DAD is done when the interface first gets the address. Before DAD the host will send a Multicast Listener Report Message to ff02::16. In the message the hosts ask to have the corresponding layer 2 address to be excluded from the filter. Then it runs DAD. If during DAD it deteremines the is a duplicate it will ask for the address to be filtered again.
How to assign link local address? What group is joined with this address is assigned?
It is automatically assigned using EUI-64 method or can be manually assigned.



EUI-64 takes 48 byte MAC address and adds FFFE in the middle and flips the 7 U/L bit.




Int e0


ipv6 address FE80::1




link-local FF02::1 multicast group is joined SNMA FF02:1::FF[last-24-bits-of-address] is joined

What are ways to assign the global address?
Static, Stateful DHCPv6, Stateless DHCPv6, and Stateless Autoconfiguration
Can we skip global configuration on p2p interfaces?
Yes, but you won't be able to remotely telnet to those interfaces.
What happens as soon as addressed is assinged?
Multicast L2 Registration and DAD
What is static configuration? What group is joined with the is added?
Static can use eui-64 like link local. Adds 16 bits in middle...FFFE and flips 7 U/L bit.



Int lo0


Ipv6 address 2001:1::1/64


Int lo0


IPv6 address 2001:1::/64 eui-64




SNMA FF02:1::FF[last-24-bits-of-address] is joined

What is stateless autoconfiguration - SLAAC?
Allows for a host to assign an address without DHCP. It listens to router advertisements to assign a prefix and uses EUI-64 to assign rest.
What must be enabled on router to send RA? How to configure router to do auto config in interface? What does host for default? What are the flags in the message?
ipv6 unicast-routing

Int e0


Ipv6 address autconfig




It will grab the link local of the sending RA for default route.


IPv6 Options - Managed and Other (off by default)


IPv6 Prefix - Local and Autoconfig (on by default)

How to configure lifetime, autoconfig flag and onlink flag for prefix.
Valid Lifetime and Preferred Lifetime.

The no means you cannot use for SLAAC.



int g0/1


ipv6 nd prefix FC00:1:0:58::/64 (lifetime-in-sec) (preferred-lifetime-in-sec) [no-autoconfig|no-onlink| off-link|




L-Bit - on by default but off-link flag disables. meaning prefix is not locally reachable. It is onlink by default.




int g0/1


ipv6 nd prefix FC00:1:0:58::/64 no-advertise




no-advertise - flag causes router not advertise that prefix.

Control SLAAC timers - Interval, lifetime, suppress
#control interval for RA

int f0/0


ipv6 nd ra interval [interval]




#control lifetime for the RA - how long to be default router


int f0/0


ipv6 nd ra lifetime [lifetime]




#configure router to suppress the RA


int f0/0


ipv6 nd ra suppress

What are the privacy extensions added to SLAAC?
RFC 4941 allows for temporary addresses to be assigned instead of the MAC addresses which is normally used with EUI-64. This is so hackers cannot predict addresses or cannot track location of mobile devices.
What does stateful DHCP need?
The client still listens to RA and the managed flag should be on and the autoconfig should be off. Client will then send a DHCP request to FF02::1:2 using it's link local.
What about stateless DHCP?
Client listens to RA and the manageged flag off, "others" flag on, autoconfig on. With autoconfig on it will auto configure address. The other flag will cause it to grab WINS, DNS, etc from server.
What is DHCP Prefix Delegation?
This allows DHCP servers to send prefixes to routers acting as DHCP clients. The addresses can in turn be used to provide prefixes in the RA.

Router DHCP Client


ipv6 enable


ipv6 dhcp client pd [name]


!


interface FastEthernet0/0


ipv6 address [name] ::1:0:0:0:1/64




Router DHCP Server


ipv6 dhcp pool dhcpv6 prefix-delegation pool dhcpv6-pool1 lifetime 1800 600


!


ipv6 local pool dhcpv6-pool1 2001:DB8:1200::/40 48

What is a 6in4, 6to4, and ISATAP tunnel?
These are all IPv6 over IPv4 tunnels.
How does 6to4 work?
6to4 works by deriving the tunnel destiniation from the IPv6 destination address. 2002::/16 is reserved for this network. The next 32 bits represent the site. This is also the tunnel source address of the remote end. My local router only needs a static route for the remote network out the tunnel. Each device must be addressed according to this site prefix.Int tu 12 ipv6 address 2002:AC10:6510::/128 tunnel source 172.16.101.1 tunnel mode ipv6ip 6to4 ipv6 route 2002:AC10:6610::/48 tun 12 172.16.102.1 = AC10:6610 that is the tunnel source.Remote Router in tu 12 ipv6 address 2002:AC10:6610::/128 tunnel source 172.16.102.1 tunnel mode ipv6ip 6to4 ipv6 route 2002:AC10:6510::/48 tun 12
Why won't 6to4 work with IGP protocols?
6to4 tunnels don't have link local addresses so IGPs don't work. Static works and BGP works because it uses the global address.
How does ISATAP differ from 6to4?
ISATAP allows network to use any IPv4 address. You configure static route to the remote destination and next hop is a link local. The link local is fe80::5efe:[last-32-bits] tunnel source. When packet leaves tunnel interface it knows what the tunnel source is based on the link local address which is configured as next-hop. Can only work with OSPF for IGPs.
What is 6rd?
6 Rapid Deployment is similar to 6to4 in that it embeds the address but the topology includes a device called a BR. Several CE are connected to a IPv4 domain. The CE networks should be configured with 6RD prefixes. When CE gets it will be able to derive the tunnel destination. If it is not to a 6rd it will send to the BR which is connected to the public or private IPv6 cloud.
What is 6PE/6VPE?
6PE is IPv6 over IPv4 MPLS network.6VPE It is MPLS L3VPN for IPv6 over IPv4 network. IPv4 is the transport protocol and IPv6 is the address family.