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Transmission of IPv6 Packets
over IEEE 802.16
draft-shin-16ng-ipv6-transmission-00
draft-shin-ipv6-ieee802.16-02
Myung-Ki Shin, ETRI
Hee-Jin Jang, Samsung AIT
IETF-65 16ng BoF @ Dallas, TX
1
Goal and Scope
• The characteristics of IEEE 802.16 networks (links)
put special considerations on how IPv6 is used
– draft-jee-16ng-ps-goals-00
• Subnet models and scenarios have an influence on
how to transmit IPv6 packets over IEEE 802.16
• Describe IPv6 operations and methods for IPv6
packet transmission over IEEE 802.16
–
–
–
–
Maximum Transmission Unit
Stateless Autoconfiguration and Link-Local Addresses
Frame Format and Encapsulation
Unicast and Multicast Transmission Methods
2
IEEE 802.16 MAC Header
• There is no source or destination MAC address in IEEE
802.16 the MAC header format.
• Instead, CID is used to identify connections to equivalent
peers in the MAC of the BS and the MS in IEEE 802.16
networks. 0
1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|H|E|
Type
|R|C|EKS|R|LEN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
LEN LSB
|
CID MSB
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
CID LSB
|
HCS
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
• [IEEE802.16] defines several CSs for carrying IP packets.
– Frame formats are different according to the CS types.
– IP(v6) CS vs. Ethernet CS.
3
Frame Format
0
1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|H|E|
Type
|R|C|EKS|R|LEN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
LEN LSB
|
CID MSB
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
CID LSB
|
HCS
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
IPv6
|
+-+
|
header
|
+-+
|
and
|
+-+
/
payload ...
/
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Frame Format for IP(v6) CS
0
1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|H|E|
Type
|R|C|EKS|R|LEN |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
LEN LSB
|
CID MSB
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
CID LSB
|
HCS
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Ethernet
|
+-+
/
header
/
/
/
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
IPv6
|
+-+
|
header
|
+-+
|
and
|
+-+
/
payload ...
/
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Frame Format for Ethernet CS
4
Stateless Auto-configuration and
Link-Local Addresses
• Like other IEEE 802 interfaces, the Interface Identifier for an
IEEE 802.16 interface is based on the EUI-64 identifier
derived from the interface's built-in 48-bit IEEE 802 address.
• The IPv6 link-local address for an IEEE 802.16 interface is
formed by appending the Interface Identifier, to the prefix
FE80::/64.
10 bits
54 bits
64 bits
+----------+-----------------------+----------------------------+
|1111111010|
(zeros)
|
Interface Identifier
|
+----------+-----------------------+----------------------------+
5
Address Mapping
• IP(v6) CS
– Mapping unicast or multicast addresses to IEEE
802.16 MAC addresses is unnecessary, since IEEE
802.16 MAC header does not contain any source or
destination 802 MAC addresses.
– To identify connections to equivalent peers in the
MAC of the BS/router and the MS, CID is used.
– Multicast CID may be provided for in the downlink.
• Ethernet CS
– Source and destination Ethernet addresses are
required to form the frame for Ethernet CS. In such
case, address mapping is the same as [RFC1972].
6
Network/Subnet Model A
• A BS is integrated with a router, composing one box
in view of implementation.
• A subnet consists of only single BS/router and single
MS.
+-----+
| MS1 |<-------------+
+-----+
v
+-----+
+-------+
+--------+
| MS2 |<---------->|BS/AR1 |---------| Edge
|
ISP
+-----+
+-------+
| Router +==>Network
+--------+
+-----+
+-------+
|
| Ms3 |<---------->|BS/AR2 |-----------+
+-----+
+-------+
<---> IP termination
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Network/Subnet Model B
• A BS is integrated with a router, composing one box
in view of implementation.
• A subnet consists of only single BS/AR and multiple
MSs.
+-----+
| MS1 |<------+
+-----+
|
+-----+
|
+-------+
+--------+
| MS2 |<------+--->|BS/AR1 |---------| Edge
|
ISP
+-----+
+-------+
| Router +==>Network
+--------+
+-----+
+-------+
|
| Ms3 |<---------->|BS/AR2 |-----------+
+-----+
+-------+
<---> IP termination
8
Network/Subnet Model C
• A BS is separated from a router
• A subnet consists of only single BS and single router
and multiple MSs.
+-----+
| MS1 |<------+
+-----+
|
+-----+
|
+-----+
+-----+
+--------+
| MSs |<------+----| BS1 |---->| AR |----| Edge
|
ISP
+-----+
+-----+
+-----+
| Router +==>Network
^
+--------+
+-----+
+-----+
|
| Mss |<-----------| BS2 |--------+
+-----+
+-----+
<---> IP termination
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Network/Subnet Model D
• A BS is integrated with a router, composing one box
in view of implementation.
• A subnet consists of multiple BS and multiple MSs.
+-----+
+-----+
+-----+
ISP 1
| MS1 |<-----+
+->| AR1 |----| ER1 |===>Network
+-----+
|
| +-----+
+-----+
+-----+
|
+-----+ |
| MS2 |<-----+-----| BS1 |--|
+-----+
+-----+ | +-----+
+-----+
ISP 2
+->| AR2 |----| ER2 |===>Network
+-----+
+-----+ | +-----+
+-----+
| Ms3 |<-----------| BS2 |--+
+-----+
+-----+
<---> IP termination
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Appendix – IPv6 Operations
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Network/Subnet Model A
• Unicast
– Outbound packet from MS is always forwarded on a particular
transport connection in the uplink direction to the BS/AR.
– When BS/AR receives the packet destined to same subnet
from MS, it does not relay the packet anymore.
– Otherwise, BS/AR forwards the packet to the edge router.
• Multicast
– Outbound packet from the MS is always forwarded on a
particular transport connection in the uplink direction to the
BS/AR.
– When BS/AR receives the packet with link-local scope from
MS, it does not forward the packet anymore.
– When BS/AR receives the packet with non-link-local scope
from MS, it looks up the IPv6 multicast routing table and
forwards the packets to the edge router.
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Network/Subnet Model B
• Unicast (Difference from Model A)
– When BS/AR receives the packet destined to same subnet
from MS but not to itself, it forwards to downlink after uplink
CID is replaced with the corresponding downlink CID (which
may be associated with the specified Ethernet addresses in
Ethernet CS or IP addresses in Ethernet/IP CS)
• Multicast (Difference from Model A)
– When BS/AR receives the packet with link-local scope from
MS, it sends back the packet to the downlink by using CID
for multicast.
13
Network/Subnet Model C
• Unicast (Difference from Model B)
– When BS receives the packet destined to different
subnet from MS, BS decapsulates the 802.16
header and forwards the packet to AR.
• In case of Ethernet CS, it will be delivered to the AR
naturally since the destination address in Ethernet header is
the AR's address.
• In case of IP CS, the BS is responsible to deliver it with the
proper Ethernet header (L2 header swapping). AR performs
routing and then forwards it to other BS or edge router
according to the routing result.
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Network/Subnet Model C, cont,.
• Multicast (Difference from Model B)
– When BS receives the packet with link-local scope from MS, it
sends back the packet to the downlink by using CID for
multicast. It also sends the packet to an AR after
decapsulating 802.16 header
– When BS receives the packet with non-link-local scope from
MS, the packet is sent back to the downlink by using CID for
multicast. It is also sent to the AR after decapsulating 802.16
header.
• In case of Ethernet CS, it will be delivered to the AR naturally
since the destination address in Ethernet header is the multicast
address.
• In case of IP CS, the BS is responsible to deliver it with the
proper Ethernet header (L2 header swapping). AR looks up the
IPv6 multicast routing table and then forwards the packets to
other BSs or edge router according to the result.
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Network/Subnet Model D
• Unicast (Difference from Model C)
– When BS/AR receives any packets from MS, BS
decapsulates the 802.16 header and forwards the packet
onto the wired network.
• In case of Ethernet CS, if the packet is destined to one of ARs,
it will be delivered to the AR naturally since the destination
address in Ethernet header is the AR's address. If the packet is
destined to MS under other BS, the target BS under which the
MS exists should catch this packet instead by acting as a
proxy of the MS and send it to MS by using corresponding
downlink CID.
• In case of IP CS, if the packet is destined to one of ARs, the
BS is responsible to deliver it with the proper Ethernet header.
If the packet is destined to MS under other BS, the target BS
should catch this packet instead by acting as a proxy of the
MS and send it to MS by using corresponding downlink CID.
16
Network/Subnet Model D, cont.
• Multicast (Difference from Model C)
– When BS receives the packet with link-local scope from MS,
it sends back the packet to the downlink by using CID for
multicast. It also sends the packet onto the wired network
after decapsulating 802.16 header. ARs will get this, and
other BSs will receive this and send it by using CID for
multicast.
– When BS receives the packet with non-link-local scope from
MS, it sends back the packet to the downlink by using CID
for multicast. It also sends the packet onto the wired network
after decapsulating the 802.16 header. Other BSs will
receive this and send it by using CID for multicast. The
multicast router receiving this will look up the IPv6 multicast
routing table and then forwards the packets to edge router
according to the result.
17