NCNU VoIP Mid-Term

Date: June 4th, 2009
Time: 9:10-11:00
(Open Book)

1. What is the header length of IPv6?
2. Explain why we do not need the field of Internet Header Length (which is required in IPv4) in an IPv6 header.
3. What is the link-local all-router multicast IPv6 address?
4. Describe the range of IPv4/IPv6 addresses that are designated to multicast destination addresses.
   
5. List the names of the five RIRs (Regional Internet Registries) in Europe, North America, Latin America, Asia-Pacific, and Africa.
6. If a host uses its IPv4 address "163.22.19.19" to build the 6to4 tunnel, what would be its /48 prefix?
7. If an ISP receives /22 IPv6 space from the NIR (National Internet Registry), how many organizations can obtain IPv6 addresses from the ISP, if each organization requires a /48 IPv6 address space?
   
8. For an IPv6-in-IPv4 tunneled packet, what is the (decimal) value of the Protocol field in IPv4 header?
   
9. If the MAC address of an interface is "00:04:76:E2:B1:BD", and the /64 prefix from the Router Advertisement is "2001:E10:6840:20", what would be the 128-bit global unicast address of this interface?
10. According to the efficiency of public IP address utilization, why is 6to4 tunneling superior to IPv4-compatible tunneling?
11. Use an example to explain why 6to4 automatic tunnel does not work when one of the tunnel endpoints is behind a NAT (network address translator).  Be sure to point out at which step the packet becomes non-routable.
    

1. 40 Bytes (Note: You cannot say "40" only.)
2. IPv6 header length is fixed.
3. FF02::2
4. IPv4: 224.0.0.0 - 239.255.255.255 (RFC 1112)
   IPv6: FF00::/8 (RFC 3513)
5. RIPE NCC, ARIN, LACNIC, APNIC, AfriNIC
6. 2002:A316:1313::/48
7. 2^(48-22)
8. 41
9. 2001:E10:6840:20:204:76FF:FEE2:B1BD
10. For IPv4-compatible tunneling, a public IPv4 address can serve only one IPv6 host.
    For 6to4 tunneling, a public IPv4 address can serve 2^16 subnets, while each subnet could serve 2^64 IPv6 hosts.
11.