1. ARP Mediation Updates Himanshu Shah Ciena Corp
Andrew Dolganow & Neil Hart Alcatel/Lucent
Eric Rosen Cisco Systems Giles Heron BT
Vach Kompella Alcatel/Lucent Andy Malis Verizon
Steven Wright AT&T Arun Vishwanathan Force10
Toby Smith NetApps Shane Amante Level 3

2. IETF-74 ARP Mediation Update 3/2009
Updates
IPv6 portion is re-written
Clarifying text added explaining why unicast traffic can not flow until ARP-mediation functions have completed.
Responded to IP Directorate review comments
Nits fixed, references updated
8/28/2018
IETF ARP Mediation Update 3/2009

3. IPv6<->Link Layer
IPv6 uses extensions of ICMP to exchange IPv6 and link address information with its neighbor
IPv6 can have more than one IPv6 addresses for a given link
IPv6 uses –
Inverse Neighbor Discovery (IND) for Point-to-point links such as FRL and ATM
Neighbor Discovery (ND) for multipoint links such as Ethernet
8/28/2018
IETF ARP Mediation Update 3/2009

4. Neighbor Discovery (ND) for Ethernet
Same as ARP, IP DA is known, DMAC is being discovered
An Ethernet based IPv6 sends ND solicitation message where –
SMAC set to sender’s MAC address, DMAC set to all-node mulitcast
IP header set to SRC IP and DST IP set to target IP
ICMP header target IP field set to target IP address
Optional Source Link address field – set to sender’s MAC address
Could contain multiple SRC IPv6 addr set
The receiver responds with ND advertisement message where
SMAC set to responder’s MAC address, DMAC set to requester’s MAC
IP header set to SRC IP set to responder’s IP, DST IP set to requester’s IP
ICMP header target IP field of requester’s IP, ‘soliciter’ bit set
Optional Target Link address MUST be set to responder’s MAC address
Unsolicited ND advertisement message can be set to notify newer info
SMAC set to advertiser’s MAC
DMAC set to all-node multicast MAC
IP header set to src IP with advertiser’s IP, dst IP set to all-node-multicast IP
ICMP header target IP field set to advertiser’s IP
‘soliciter’ bit is reset, ‘override’ bit set
8/28/2018
IETF ARP Mediation Update 3/2009

5. Inverse Neighbor Discovery (IND)
IND is typically used for point-to-point links such as ATM and FRL where SRC and DST Link information is known and seeking Destination IP address.
IND solicitation has
IP header with SRC-IP set to sender’s IP and DST-IP set to all-node-multicast IP
ICMP fields have source and target link fields set to sender and target’s link and optional list of source IP addresses configured on that interface
IND advertisement has
IP header with SRC-IP set to responder’s IP, DST-IP set to requester’s IP
ICMP fields have, source and target link fields set to responder and requester’s link address, target address list set to responder’s IP addresses configured on the interface
8/28/2018
IETF ARP Mediation Update 3/2009

6. IETF-74 ARP Mediation Update 3/2009
Scheme Overview
Use of ICMPv6 allows use of IP PW as compared to ARP packets that are non-IP PDU
Let ICMPv6 packets flow across IP PW
Let both PEs learn local/remote CE’s IP address information by snooping ICMPv6 packets from local AC and PW
In case of disparate neighbor discovery scheme, provide appropriate termination/reciprocation functions (details follow).
8/28/2018
IETF ARP Mediation Update 3/2009

7. IETF-74 ARP Mediation Update 3/2009
Both CEs are Ethernet
Eth
MPLS
Eth
CE1
PE1
PE2
CE2
timeline
ND-Sol
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
ND-Sol
ND-Sol
Src MAC=PE2
Learn CE2’s
Link & IP list
ND-Adv
Learn CE2’s
IP addr list
ND-Adv
ND-Adv
Src MAC=PE1
8/28/2018
IETF ARP Mediation Update 3/2009

8. Both CEs are Ethernet but uses ND-Adv only
MPLS
Eth
CE1
PE1
PE2
CE2
timeline
ND-Adv
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
ND-Adv
ND-Adv
Src MAC=PE2
Learn CE2’s
Link & IP list
ND-Adv
Learn CE2’s
IP addr list
ND-Adv
ND-Adv
Src MAC=PE1
8/28/2018
IETF ARP Mediation Update 3/2009

9. Both CEs are point-to-point
FRL
MPLS
FRL
timeline
CE1
PE1
PE2
CE2
IND-Sol
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
IND-Sol
IND-Sol
Src DLCI=PE2
Learn CE2’s
Link & IP list
IND-Adv
Learn CE2’s
IP addr list
IND-Adv
IND-Adv
Src DLCI=PE1
8/28/2018
IETF ARP Mediation Update 3/2009

10. CE1 is Eth, CE2 is FRL (option 1)
MPLS
FRL
timeline
CE1
PE1
PE2
CE2
ND-Sol
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
ND-Sol
ND-Sol
Src DLCI=PE2
Learn CE2’s
Link & IP list
IND-Sol
Learn CE2’s
IP addr list
IND-Sol
Since CE1’s
IP Addr is known
IND-Adv
IND-Adv
ND-Adv
Src DLCI=PE2
Src MAC=PE1
Two Actions
8/28/2018
IETF ARP Mediation Update 3/2009

11. CE1 is Eth, CE2 is FRL (option 1)
MPLS
FRL
timeline
CE1
PE1
PE2
CE2
Learn CE2’s
Link & IP list
IND-Sol
Learn CE2’s
IP addr list and discard
IND-Sol
ND-Sol
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
ND-Sol
ND-Sol
Src DLCI=PE2
Learn CE2’s
Link & IP list
PE1 knows CE1’s
IP addr so send IND-adv on PW and ND-adv on local AC
IND-Sol
IND-Sol
IND-Adv
IND-Adv
ND-Adv
Src MAC=PE1
Src DLCI=PE2
Two Actions
8/28/2018
IETF ARP Mediation Update 3/2009 11

12. CE1 is Eth, CE2 is FRL (option 2)
MPLS
FRL
timeline
CE1
PE1
PE2
CE2
ND-Sol
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
ND-Sol
IND-Sol
Src DLCI=PE2
Learn CE2’s
Link & IP list
IND-Adv
Learn CE2’s
IP addr list
IND-Adv
ND-Adv
Src MAC=PE1
8/28/2018
IETF ARP Mediation Update 3/2009

13. CE1 is Eth, CE2 is FRL (option 2)
MPLS
FRL
timeline
CE1
PE1
PE2
CE2
IND-Sol
IND-Sol
Learn CE2’s
IP addr list
Learn CE2’s
IP addr list and discard
ND-Sol
Learn CE1’s
Link Addr & IP
Learn CE1’s
IP addr list
ND-Sol
IND-Sol
Src DLCI=PE2
Learn CE2’s
Link & IP list
Learn CE2’s
IP addr list
IND-Adv
IND-Adv
ND-Adv
Src MAC=PE1
8/28/2018
IETF ARP Mediation Update 3/2009 13

14. IETF-74 ARP Mediation Update 3/2009
Conclusion
We believe draft is ready for one more final call and then be sent for RFC approval
The applicable IPv6 related changes from this draft will be ported to IPLS draft and will be submitted for final call
8/28/2018
IETF ARP Mediation Update 3/2009