The models use Check Point's FireWall-1 Next Generation software and are intended to offer flexible security options to customers with a wide range of users, bandwidth and security needs.
The Alteon Switched Firewall 5710, for example, is aimed at large enterprises and service providers and offers more than 4Gbps of throughput, 32,000 sessions per second and support for up to one million concurrent sessions.
The Alteon 5100, on the other hand, is a low-end, non-accelerated switched firewall for organisations in need of basic firewall protection.
The announcement is the latest in a series of measures by Nortel to court the enterprise hardware market, which is dominated by Cisco.
Last month, the company unveiled its Unified Security Architecture program, an effort to sell customised and scalable network, application and management security products to enterprise customers.
Nortel also recently announced a restructuring and the introduction of a new business unit focused exclusively on enterprise networks.
"The problem Nortel faces is that the enterprise market for firewalls is pretty well understood and pretty well set," said Laura Koetzle, an analyst at Forrester Research.
"Companies like Cisco, NetScreen, Nokia, and Check Point pretty much have the enterprise firewall market figured out. And, while I have no doubt that [the new Alteon models] are good products, they're going to have to severely undercut the existing players on price to get a piece of the market," Koetzle said.
Nortel built its reputation as a supplier for large infrastructure companies such as telecommunications and service providers. As the fortunes of those companies rose during the bull market of the 1990s so did Nortel's, which commanded a share price of more than $75 at the height of the Internet bubble in spring 2000.
However, the collapse of the telecommunications sector has hit Nortel's sales hard, with most telecommunications companies cutting jobs and severely restricting spending on hardware.
The company lost a total of $24bn (£15.45bn) in 2001. Nortel also posted a net loss in the second quarter of $697m, compared with a net loss of $16.64bn in the same period last year.
While Nortel's firewalls may offer customers an advantage in terms of flexibility and performance, analysts say the company will have to do more to woo customers away from companies that already have a strong foothold in the enterprise market.