Requirements for DRNI on layer 3 gateway devices

1
Requirements for DRNI on layer 3 gateway devices

• 802.1 AX-REV, 201203 IEEE 802 plenary
• Lu Huang (huanglu_at_chinamobile.com)

2
Agenda

• Use case
• Requirement
• Proposal

3
Use cases

• Use case 1 Mobile backhaul
• In LTE mobile backaul, one optional solution is
  deploying routers and layer 2 network(PTN). For
  the interconnection between routers and PTN, DRNI
  is an appropriate mechanism
• Router is the Layer 3 gateway of eNodeBs. In this
  case, DRNI is used on layer 3 gateway devices
• Furthermore, In the best case convergence time
  should be less than 200ms, in the worst case it
  should be less than 500ms

DRNI

• Use case 2 Layer 2 network in cloud computation
  IDC
• In cloud computation IDC, we use layer 2 network
  to meet the requirement of cloud computation. We
  want to use DRNI instead of spanning tree (Of
  course, SPB or Trill are also optional, maybe in
  the future)
• Core switch is the layer 3 gateway of servers. In
  this case, DRNI is used on layer 3 gateway
  devices
• Furthermore, convergence time should be less than
  500ms

DRNI
DRNI

1. We want to use DRNI on layer 3 gateway devices
2. We require fast convergence in DRNI for protection

4
Agenda

• Use case
• Requirement
• Proposal

5
Requirement(1)Unique MAC for DRNI
Layer 3 network

• For hosts there should be only one gateway, so
  GW1 and GW2 should share the same MAC and IP
  address for LA1 (the distributed link aggregation
  group)
• When hosts request GWs ARP, GW1 and GW2 should
  answer the same ARP ( GW_IP, unique MAC)
• When GW1 and GW2 request hosts ARP, they should
  use the same sender ARP info ( GW_IP, unique MAC)
• Because GW1 and GW2 will use LA1s MAC as their
  ARP MAC, so DRNI should make sure that nodes in
  the same DAS share an unique MAC which could be
  used by upper layer protocol (e.g. ARP)
• We can config the same IP on LA1 of GW1 and GW2.
  It doesnt depend on DRNI protocol

GW1
GW2
LA1
LA2
L2SW1
L2SW2
Layer 2 network
L2SW
Host
ARP Request
ARP Reply
6
Requirement(2)L3 entries Backup mechanism

• To obtain fast protection switch, GW1 and GW2
  should share the same L3 entries (e.g. ARP
  entries). When GW1 or link between GW1 and L2SW1
  break down, GW2 could forward all flows
  immediately
• Real-time backup
• When GW1 receives ARP request or ARP reply packet
  from host, it should duplicate one and send to
  GW2
• When GW2 receives ARP request or ARP reply packet
  from host, it should duplicate one and send to
  GW1
• GW1 and GW2 could limit the duplication based on
  the ETH_TYPE of packets ( for ARP, its 0x0806)
• This mechanism could not used in the below
  scenario
• Batch backup
• When GW1 reboots, batch backup(with GW2) can help
  GW1 recover forwarding all flows as soon as
  possible. Otherwise GW1 wil take even a few
  seconds to relearn ARP entries and introduce a
  long interruption
• How to fulfill batch backup is under research (
  through ICCP, LACP or ARP )
• Of course, if we define a protocol for batch
  backup, it also could be used for real-time backup

Layer 3 network
GW1
GW2
L2SW1
L2SW2
Layer 2 network
Host
ARP Request or Replay
7
Agenda

• Use case
• Requirement
• Proposal

8
Proposal

• When using DRNI on layer 3 gateway devices, DRNI
  should support the following features
• Nodes in the same DAS share an unique MAC for LA
  group
• A node could duplicate some certain packets to
  the other nodes in the same DAS based on ETH_TYPE
  of packets
• Nodes in the same DAS could fulfill batch backup
  of certain entries (e.g. ARP entries) with each
  other

9
Thank youQA