InterSwitch Trunk
Encyclopedia
InterSwitch Trunk is one or more parallel point-to-point links (Link aggregation
) that connect two switches together to create a single logical switch. The IST allows the two switches to share addressing information, forwarding tables, and state information, permitting rapid (less than one second) fault detection and forwarding path modification. The link may have different names depending on the vendor. For example, Brocade calls this an Inter-Chassis Link (ICL). Cisco calls this a VSL (Virtual Switch Link).
Edge switches, servers or PC's see the two aggregate switches as one large switch. This allows any vendor's equipment configured to use the IEEE 802.3ad static link aggregation protocol to connect to both switches and take advantage of load balancing, redundant connections.
The IST protocol was developed by Nortel
(now acquired by Avaya
) to enhance the capabilities of Link aggregation
, and is required to be configured prior to configuring the SMLT, DSMLT or R-SMLT
functions on the two aggregate (core, distribution, or access) switches. The edge equipment can be configured with any of the following; Multi-Link Trunking (MLT), DMLT, IEEE 802.3ad static link aggregation, IEEE 802.3ad Static Gigabit EtherChannel (GEC), IEEE 802.3ad Static Fast EtherChannel (FEC), SMLT, DSMLT, and other static link aggregation protocols.
and MERS 8600 products.
Link aggregation
Link aggregation or trunking or link bundling or Ethernet/network/NIC bonding or NIC teaming are computer networking umbrella terms to describe various methods of combining multiple network connections in parallel to increase throughput beyond what a single connection could sustain, and to provide...
) that connect two switches together to create a single logical switch. The IST allows the two switches to share addressing information, forwarding tables, and state information, permitting rapid (less than one second) fault detection and forwarding path modification. The link may have different names depending on the vendor. For example, Brocade calls this an Inter-Chassis Link (ICL). Cisco calls this a VSL (Virtual Switch Link).
Edge switches, servers or PC's see the two aggregate switches as one large switch. This allows any vendor's equipment configured to use the IEEE 802.3ad static link aggregation protocol to connect to both switches and take advantage of load balancing, redundant connections.
The IST protocol was developed by Nortel
Nortel
Nortel Networks Corporation, formerly known as Northern Telecom Limited and sometimes known simply as Nortel, was a multinational telecommunications equipment manufacturer headquartered in Mississauga, Ontario, Canada...
(now acquired by Avaya
Avaya
Avaya Inc. is a privately held computer networking, information technology and telecommunications company that is a global provider of business communications systems. The international head quarters is in Basking Ridge, New Jersey, United States...
) to enhance the capabilities of Link aggregation
Link aggregation
Link aggregation or trunking or link bundling or Ethernet/network/NIC bonding or NIC teaming are computer networking umbrella terms to describe various methods of combining multiple network connections in parallel to increase throughput beyond what a single connection could sustain, and to provide...
, and is required to be configured prior to configuring the SMLT, DSMLT or R-SMLT
R-SMLT
Routed-SMLT is a computer networking protocol designed by Nortel as an enhancement to SMLT enabling the exchange of Layer 3 information between peer nodes in a Switch Cluster for unparalleled resiliency and simplicity for both L3 and L2.In many cases, core network convergence-times after a...
functions on the two aggregate (core, distribution, or access) switches. The edge equipment can be configured with any of the following; Multi-Link Trunking (MLT), DMLT, IEEE 802.3ad static link aggregation, IEEE 802.3ad Static Gigabit EtherChannel (GEC), IEEE 802.3ad Static Fast EtherChannel (FEC), SMLT, DSMLT, and other static link aggregation protocols.
Product Support
IST is supported on Nortel's Routing Switch 1600, 5500, 8300, ERS 8600Nortel ERS 8600
The Avaya Ethernet Routing Switch 8600 or ERS 8600, previously known as the Passport 8600 or the Accelar 8000, is a modular chassis combination hardware router and switch used in computer networking, designed and manufactured by Avaya...
and MERS 8600 products.