Term
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Definition
| RIP next generation (RIPng) is still the same as RIPv2, with a 15-hop limit, counting to infinity, and split horizon with poison reverse. But now uses UDP port 521 (instead of UDP 520). RIPng uses multicast group FF02::9 for RIP updates to all RIP routers |
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Term
| What does IPv6 use in regards to ICMP? |
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Definition
| IPv6 used ICMPv6, which all IPv6 nodes must implement to preform network layer functions. Instead of using IP protocol 1 like ICMPv4, IPv6 uses a next header number of 58 |
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Term
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Definition
| Cisco developed EIGRP with IPv6 support. EIGRP for IPv6 is configured and managed separately from EIGRP for IPv4, but has all the same characteristics and functions. EIGRP used multicast group FF02::A for EIGRP updates. |
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Term
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Definition
| 6to4 is the method for creating tunnels for IPv6. It assigns 2002::/16 as an interim unique IPv6 prefix. Each 6to4 site used a /48 prefix that is concatenated with 2002. |
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Term
| What are IPv6 multicast addresses? |
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Definition
| The IPv6 multicast (one-to-many) address identifies a set of hosts. Its similar to an IPv4 multicast address, but supersedes the broadcast function of IPv4 broadcast. You use an "all-nodes" multicast address instead. |
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Term
What are the IPv6 multicast groups for the following protocols:
- RIPng
- EIGRP
- OSPF (all routers)
- OSPF (designated routers) |
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Definition
- RIPng = FF02::9
- EIGRP = FF02::A
- OSPF (all routers) = FF02::5
- OSPF (designated routers) = FF02::6 |
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Term
| What 2 integrated mechanisms provide security for IPv6? |
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Definition
| It natively supports IPsec. Extension headers carry the IPsec AH and ESP header. The AH provides authentication and integrity. The ESP header provides confidentiality by encrypting the payload . For IPv6, the AH defaults to MD5 and ESP encryption defaults to DES-CBC |
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Term
| What are some routing protocols supported by IPv6? |
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Definition
- RIPng
- Integrated IS-IS
- EIGRP for IPv6
- OSPFv3
- BGP |
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Term
| What are some of the functions preformed by the IPv6 ND protocol? |
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Definition
- Address auto configuration
- Duplicate address detection
- Prefix discovery
- Parameter discovery
- Address resolution
- Router discovery
- Next-hop determination
- Neighbor unreachability detection
- Redirect |
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Term
| What is the format for an IPv6 global unique address? |
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Definition
|---network portion----|--host portion--|
|---48 bits----|16 bits|----64 bits-----|
global routing prefix|subnet ID|interface |
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Term
| How are IPv6 addresses displayed? |
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Definition
| The IPv6 addresses have 8 16-bit groups. The hexadecimal value is x:x:x:x:x:x:x:x, where each "x" represents 4 hexadecimal digits (16 bits) |
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Term
| What type of DNS records are used for IPv6 name resolution? |
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Definition
| IPv6 used a new type of resource record known as an AAAA, or quad-A. There is also an A6 resource record, the provides additional features and is intended to replace the quad-A |
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Term
| How can IPv4 addresses be mixed with IPv6 addresses? |
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Definition
| By using just the last 2 16-bit blocks of an IPv6 address for IPv4. The first 6 blocks are represented as 0's |
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Term
| What are the ICMPv6 messages used by IPv6 ND to implement some of its functions? |
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Definition
- Router solicitation(RS) - sent by hosts to request RAs from local routers
- Router advertisements(RA) - sent by routers to advertise their presence and link-specific parameters
- Neighbor solicitation(NS) - sent by hosts to request link layer addresses of other hosts. Also used for duplicate address detection.
- Neighbor advertisements(NA) - sent by hosts responding the NS's
- Redirect - sent to a host to notify it of a better next hop to a destination |
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Term
| What are IPv6 anycast addresses? |
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Definition
| The IPv6 anycast (one-to-nearest) address identifies a set of devices. An anycast address is allocated from a set of unicast addresses. You can use the anycast address to identify a set of routers or servers. When a packet is sent to the anycast address, it is delivered to the nearest device as determined by the routing protocol. |
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Term
| What is the IPv6 loopback address? |
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Definition
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Term
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Definition
| OSPFv3 algorithms and mechanisms remain the same for IPv6, but support IPv6 addresses, address hierarchy, and IPv6 for transport. OSPFv3 uses multicast group FF02::5 for all OSPF routers and FF02::6 for all designated routers. |
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Term
| With IPv6, what is an unspecified address? |
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Definition
| An unspecified address is all 0's, 0:0:0:0:0:0:0:0. It signifies that an IPv6 address is not specified for the interface. Unspecified addresses are not forwarded by an IPv6 router. |
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Term
| What happens when a packet size is greater than the interfaces MTU? |
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Definition
| The layer fragments the packet, which is not reassembled until it reaches the destination IP layer. The destination host preforms the reassembly and places the fragments in the correct order by looking at the identification and fragment offset fields. If one or more of the fragments is lost, the entire packet must be retransmitted. |
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Term
| How does packet fragmentation work with IPv6? |
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Definition
| IPv6 does not allow packet fragmentation throughout the internetwork. Only hosts are allowed to fragment. Routers are not allowed to fragment packets. The MTU of every link in an IPv6 must be 1280 bytes or greater, Nodes should implement IPv6 path MTU discovery to determine if any paths are greater than 1280 bytes. ICMPv6 packet-too-big error messages determine the path MTU |
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Term
| Describe the deployment model of IPv6 over dedicated WAN links |
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Definition
| All nodes and links use IPv6 hierarchy, addressing, and protocols. It is not a transition model, but a new, separate deployment of IPv6. The disadvantage is that additional costs are incurred when separate links are used for IPv6 WAN circuits during the transition to use IPv6 exclusively. |
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Term
| What are some of the enhancements of IPv6 over IPv4? |
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Definition
- Expanded address space - 128-bit vs. 32-bit
- Globally unique addresses - eliminating NAT
- Fixed header length - improves switching efficiency
- Improved option mechanism - options are placed in separate optional headers located between IPv6 headers and transport headers
- Address auto configuration - no need for DHCP
- Support for labeling traffic flows - instead of type of service (ToS) field
- Security capabilities - support authentication and privacy
- MTU path discovery - eliminates need to fragment packets
- Site multihoming - allows multihoming of hosts and networks to have multiple IPv6 prefixes. |
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Term
| How does a host determine what stack to use in a dual-stack environment? |
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Definition
| A host used DNS to determine which stack to use to reach a destination. If DNS returns an A6 record, it uses IPv6, or uses IPv4 if it gets an A record. |
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Term
| What does IPv6 use instead of ARP? |
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Definition
| IPv6 implements the network discovery (ND) protocol. Hosts use the ND protocol to implement plug-and-play functions that discover all other nodes in the same link, check for duplicate addresses and finds routers on the link. |
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Term
| What are some short-hand ways of writing an IPv6 address? |
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Definition
- Groups with a value of 0 can be represented with a single 0
- You can represent multiple groups of 16-bit 0's with "::", which may appear only once in a number
- You do not need to represent leading 0's in a 16-bit piece |
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Term
| IPv6 unicast addresses are divided into what 2 types? |
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Definition
| Global and link-local address |
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Term
| With the differentiated services field in an IPv4 header, how many levels of classification are there using differentiated services check point (DSCP)? |
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Definition
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Term
1. What are IPv6 link-local addresses?
2. How are link-local addresses identified?
3. What is the format of a link-local address? |
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Definition
1. IPv6 link-local addresses are significant only to the nodes on a single link, so routers do not forward packets with a link-local source or destincation beyond the local link.
2. Identified by leading FE8 hexadecimal numbers
3. The format o the link-local address is an FP of 1111111010 followed by 54 0's, and a 64-bit interface identifier (ID)
FE80::/64 |
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Term
| What are the available deployment models that exist to migrate from IPv4 networks to IPv6? |
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Definition
- IPv6 over dedicated WAN links
- IPv6 over IPv4 tunnels
- IPv6 using dual-stack backbones
- Protocol translation |
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Term
| How does protocol translation work between IPv6 and IPv4? |
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Definition
| IPv6 can use NAT-PT, which provides translation between IPv6 and IPv4 hosts. NAT-PT binds addresses in the IPv6 network to addresses in the IPv4 network and vise versa. |
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Term
| Describe the deployment model of dual-stack backbones |
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Definition
| All routers on the backbone are dual-stack, capable of routing IPv4 and IPv6 packets. The disadvantage s that the WAN routers require dual addressing, run 2 routing protocols, and might require additional CPU and memory resources. Also, IPv4-only and IPv6-only host cannot communicate with each other directly; dual stack host or network translation is required. |
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Term
1. How are IPv6 multicast addresses identified?
2. What is the format of an IPv6 multicast address? |
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Definition
1. By the leading FF hexadecimal numbers
2. 8 bits network, 4 bits FLGS, 4 bits SCOP, and 112 bits group ID |
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Term
| with IPv4, what is the maximum length of an IP packet? |
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Definition
| The maximum length of an IP packet is 65535, but most common lower-layer protocols do not support that large of MTU |
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Term
| Describe the deployment model of IPv6 over IPv4 tunnels. |
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Definition
| Packets of IPv6 networks are connected using IPv4 tunnels. The IPv6 traffic is encapsulated within IPv4 packets so that they are sent over the IPv4 WAN. The advantage is that you do not need separate circuits to connect the IPv6 networks, but it does increase protocol overhead for the encapsulation of IPv6 heads. Tunnels are created using 6to4. |
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Term
| What are the 3 types of IPv6 addresses? |
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Definition
- Unicast
- Anycast
- Multicast |
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Term
| Without any options, what is the length of an IPv4 header? |
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Definition
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