Joint IEEE-SA and ITU Workshop on Ethernet. 802.1AX-REV – Link Aggregation Revision. Panagiotis Saltsidis, Senior Specialist, Ericsson. Link aggregation. Link Aggregation was originally standardized in 802.3ad-2000 (it has been later incorporated in 802.3 as clause 43 of 802.3-2005).
Link Aggregation—DRNIprovides benefits of Link Aggregation
Portals—Connections between two cooperating sets of Systems (two Portals) are supported, in contrast to Link Aggregation defined by previous versions of the standard, so that connectivity between two networks can be maintained despite the failure of an entire System (and its connected links) belonging to a Portal.
Compatibility—A multi-System Portal can connect to a single-System Portal or to an Aggregation System compliant with previous versions of this Standard.
Administrative isolation—ADRNI Link Aggregation Group can connect Portals in networks that are under separate administration, running different fault recovery protocols.
Administrative independence—Thespecification of DRNI to interconnect separate networks does not introduce new requirements on either networks’ existing control protocols.
Inter-network fault isolation—The failure or recovery of a link or node in one network, requiring a reaction by that network’s control protocols, can be hidden by DRNI from the second network’s control protocols. Thus, super-networks can be created out of separate networks interconnected via DRNI, without propagating one network’s fault and recovery events throughout the super-network.
Network-DRNI fault isolation—The failure or recovery of a link between two Portals can be hidden by DRNI from both networks’ control protocols.
Rapid fault recovery—Meansfor the Systems in a Portal to communicate are provided so that they can cooperate to respond rapidly to failure or recovery events, typically on the order of milliseconds for link down events and 1 second or less for link up events.
Extended faults—Optionalelements of DRNI can support three Systems in a Portal, so that fault redundancy can be provided even while a System is added or removed from a Portal.
Distribution independence—Theframe distribution algorithm used to satisfy network requirements can be different from the algorithm used to assign frames to the Aggregation Ports of a Link Aggregation Group.
DRNI is created by using a Distributed Relay to interconnect two or three Systems, each running Link Aggregation, to create a Portal.
Each System in the Portal (i.e., each Portal System) runs Link Aggregation with a single Aggregator.
The Distributed Relay enables the Portal Systems to jointly terminate a Link Aggregation Group.
To all other Systems to which the Portal is connected, the Link Aggregation Group appears to terminate in a separate emulated System created by the Portal Systems
Systems A and B each is characterized by performing a “Function 1,” which is presumably some kind of packet relay function, e.g., a router or a bridge.
“Function 1” could just as well be a file server operation, in which case the outside two “ports” on each System would likely not be present.
Each system runs a single instance of a Link Aggregation sublayer.
In each System A and B, the ports that are to be associated with System C are moved to a position below the DR Function’s Link Aggregation sublayer.
A virtual link and its terminating virtual MACs, called a “Gateway”, is constructed to connect each DR Function to its Function 1.
Between each pair of DR Functions in the Portal there is constructed an Intra-Portal Link (IPL), terminated at each end by an Intra-Portal Port (IPP).
There is a “Gateway algorithm” that decides through which Gateway a frame can pass into or out of the emulated Distributed Relay.
Similarly, a “Port algorithm” decides through which Portal System’s Aggregation Ports a frame can pass into or out of the emulated Distributed Relay.
The DR Functions, work together to move frames between the Gateways, the IPLs, and the Link Aggregation sublayers.
IEEE802.1AX-REV will not define the alternate model shown in Figure above, in which the entirety of Systems A and B simulate a single System D, but neither will it prevent the use of DRNI in such a model
The 6th Task Group Ballot will be discussed during this meeting
The aim is have new drafts and associated ballots per IEEE802.1 meeting
The goal is to have an approved and published standard during the first half of 2014