Max Riegel 2006-07-07

Transmission of IP Packets over Ethernet over IEEE802.16draft-riegel-16ng-ip-over-eth-over-80216-00

Max Riegel <[email protected]> 2006-07-07

16ng@IETF-66 IEEE802.16 Fixed/nomadic deployment (Max Riegel)

Introduction

Goal of this presentation Present draft-riegel-16ng-ip-over-eth-over-80216-00.txt Introduce topic and particular issues with Ethernet over IEEE802.16 Provide background information on IEEE802.16 link behavior Outline solution approaches Promote contributions from others

Status of draft-riegel-16ng-ip-over-eth-over-80216-00.txt Initial I-D Provides outline and hints, how the solution may look like IPv4 solution based on results out of WiMAX NWG Lots of material still missing


IP works fine over Ethernet

RFC 894 defines transmission of IPv4 packets over Ethernet RFC 826 recommends the use of ARP for address resolution

RFC2464 specifies the transmission of IPv6 packets over EthernetToday most Ethernets are (bridged) switched LANs with point-to-

point links between Switch and HostNo issues when there is sufficient bandwidth and power Usually the case for wired Ethernets

Wireless issues: shared transmission resource and limited power. Power issue may even be more critical than scarce transmission

resource

Internet

Internet


Protocol Layering of the IEEE 802.16 Standard

Physical Layer, MAC Common Part Sublayer and Management/Control Plane are agnostic to user payload (CS type)

Standard accommodates multiple instantiations of CS types

Classification is specific to particular CS type e.g. for IPoETH-CS, 14-18 bytes of

additional header information must be parsed per packet.


Convergence SublayerClassification & Encapsulation

Packet-handling in the base station is done based on information in the packet header

Classification based on header information

Encapsulation and forwarding


The IEEE802.16 Link Model

IEEE802.16 provides point-to-point links between the BS and MS No direct communication between terminals possible

Fits well into switched Ethernet model

CS SAP

Service SpecificConvergence Sublayer

(CS)

MAC SAP

MAC Common PartSublayer

(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

MAC

PHY

IEEE802.16/802.16e Data/Control Plane

PHS (opt.)

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

1

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

3

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

5

Clas

sifie

r

CID#

6CI

D#4

CID#

2

MS MS MS BS

APPL APPL APPL

Radio


Switched Ethernet link model for IEEE802.16

Switch in basestation broadcasts packets to all MSs, if destination MAC address is not known in the switch Waste of radio resource All terminals have to wake up to process broadcast packet

CS SAP


(CS)

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

MAC

PHY


PHS (opt.)

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

1

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

3

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

5

Clas

sifie

r

CID#

6CI

D#4

CID#

2

MS MS MS BS

APPL APPL APPL

Radio


Enhanced Ethernet link model for IEEE802.16

Dedicated switch functions prevent the ‘unnecessary’ transmission of ETH frames over the air Response to broadcast and multicast requests on behalf of the MSs Must learn about the MAC & IP addresses of the MSs

CS SAP


(CS)

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

MAC

PHY


PHS (opt.)

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

1

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

3

Clas

sifie

r

CS SAP

MAC SAP


(MAC CPS)

Privacy Sublayer

Physical Layer(PHY)

PHY SAP

PHS (opt.)

CID#

5

Clas

sifie

r

CID#

6CI

D#4

CID#

2

MS MS MS BS

APPL APPL APPL

Radio


IPv4 specific behavior of the bridging function

Proxy ARP function The BS SHALL support Proxy-ARP. The BS SHALL have the ability to enable or disable Proxy ARP. If Proxy ARP is disabled, the ARP

Proxy Agent shall pass all ARP packets without discrimination or modification using Standard Learned Bridging.

Upon receiving an ARP Request from a network side interface, the ARP Proxy Agent shall unicast an ARP Response back to that interface, provided that the target address matches an entry in the Proxy ARP table. If no match is found in the Proxy ARP table, the ARP Proxy Agent SHALL support silently discarding the Request or flooding the Request to all radio connection interfaces based upon configuration option.

The ARP Proxy Agent shall pass all ARP Response packets without discrimination or modification using Standard Learned Bridging. Upon receiving an ARP Request from an radio connection interface, the ARP Proxy Agent shall unicast an ARP Response back to the interface provided that the target address matches an entry in the Proxy ARP table. Otherwise, the ARP Proxy Agent shall flood the Request to all network side interfaces.

The ARP Proxy Agent shall silently discard any received self-ARP Requests. Those are requests for a target IP address, that when queried in the Proxy ARP table results in a response MAC equal to the Request's source MAC address.

The ARP Proxy Agent shall issue a gratuitous ARP on the network side interfaces for any new addition to the Proxy ARP table. An unsolicited broadcast ARP Response constitutes a gratuitous ARP. The Proxy ARP table MAY be established out of other IPv4 specific information available in the BS, e.g. DHCP Proxy or MIPv4 FA. The particular procedures are implementation dependent.

Information for the Proxy ARP Table MAY be transferred during handover of a mobile IEEE802.16e station to the target BS. The particular protocol for transfer of information for the Learned Bridge Table is out of scope of this specification.


IPv6 specific behavior of the bridging function

t.b.f.


Conclusion

Current specification makes no use of MBS feature of IEEE802.16 MAC MBS may not provide essential benefits for supporting multicast

• Power consumption issue may be more important than radio resource issue• Proxy functions in bridge at BS may gain more than enhancements to the

multicast behavior of IEEE802.16

Need for context transfer between proxy tables during handover Learned table entries may efficiently be reused by the target BS Open: context transfer protocol


Questions & Comments

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Max Riegel 2006-07-07

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