Alcatel last week announced what it claims is the first "nonstop" routing technology for the three most widely used routing protocols.
The Alcatel Carrier Environment Internet System (ACEIS) is said to eliminate core network downtime traditionally caused by corrupt routing information or routine software upgrades. ACEIS is a combination of hardware and software that is integrated with Alcatel core networking products, including the company's 7770 Routing Core Platform and 7670 Routing Switch Platform.
ACEIS is designed for the BGP, OSPF and IS-IS routing protocols. BGP has proven to be the most difficult protocol to adapt to nonstop routing, due to the large amount of TCP session information that must be maintained at all times, Alcatel says.
This is especially important during software upgrades and control-complex switchovers, the company says.
Analysts say ACEIS may be unique but it's hard to tell because Alcatel is disclosing little technical detail into its inner workings.
"This is the first time I've seen Tandem or Stratus applied to routing," IDC Analyst Paul Strauss says, comparing ACEIS to the fault-tolerant offerings of two computers companies that no longer exist. "Other approaches, such as Virtual Router Redundancy Protocol [VRRP] in routing, and Spanning Tree and Rapid Spanning Tree in switching, rely on network techniques to divert traffic between processors or around a failed processor. ACEIS could reduce the need for such techniques, since a router or switch would never fail, barring an external disaster."
Strauss says ACEIS is the equivalent of two or more routers within a single box, with a "special kind of software" to switch among them.
"The hardware implementation is not physically the same as having two routers or switches within the same chassis, but it amounts to the same thing," he says.
On the software front, the approach works by having at least two sets of routing tables operating at all times on different processors. This means an in-service set of tables and a back-up set.
"It is likely that routing updates go simultaneously to both tables," Strauss describes. "Key to the system, as is the case with nonstop computers, is special software that monitors the system to detect failure and switches from the in-service to the back-up table. This process is similar to VRRP, differing in being much faster."
Alcatel will not discuss the time involved in such a swap, but apparently it is in the area of hundredths of a second or possibly faster, as opposed to the minute to several minutes of VRRP, Strauss says.
ACEIS will appeal to service providers that now purchase, install, operate, manage and maintain at least two routers for redundancy.
"Few service providers that install dual routers with a slow failover between them would do so if they could obtain a single router with a very fast failover between internal systems," Strauss says.
ACEIS products are set to be unveiled at SuperComm 2002 in June.