Solaris DNS and Alteon NS

[Jo]

I am using a Solaris 7 DNS server in an old box. The server was setup
3 years ago with with a few lines:

;     define the nameservers and mail servers.
          IN     NS     ns.xyz.com.
          IN     MX     5 mail.xyz.com.
;     define localhost
localhost     IN     A     127.0.0.1
;     define the hosts in this zone.
ns          IN     A     205.15.6.8
mail        IN     A     205.15.6.10
www         IN     A     205.15.6.47
ftp         IN     A     205.15.6.2

We are planning to use two Alteon switches with 2 ISP's. The Alteon
swich will respond to DNS query's, so will be two entrys on the DNS
table.

Here is the proposed configuration which should be added on the DNS
server:

www2        IN     NS     ns-ca     # create and
            IN     NS     ns-co     # delegate
ns-ca       IN     A     200.200.200.100     # glue
ns-co       IN     A     174.14.70.100     # glue
@           IN     A     200.200.200.1     # for foocorp.com
            IN     A     174.14.70.1     # for foocorp.com
www2-ca     IN     A     200.200.200.1     # for Redirects
www2-co     IN     A     174.14.70.1     # for Redirects

I would like to maintain the old entry's for mail, www and ftp and
add another entry for www2 just to verify the configuration.

My question is how this configuration will work? What is use @ for? 
Can somebody help me with a short explanation.


Thanks
joe