Access Servers


Introduction.  Access Servers connect users to internetworks over normal telephone lines.  There purpose is to provide authentic remote users internetwork ready connections.  These users might be mobile users, typical home users dialing into an ISPor at a small branch office.  Access servers are equipped with hardware and software especially designed to work within typical internetworks but also provide modems to serial telephone lines.

Typically they are used to perform one or all of the following.

  • Terminal service - connecting asynchronous devices using terminal emulation software.
  • Protocol translation service - convert remote user's virtual terminal protocol to another.
  • Telecommuting service
  • Routing service - IP routing functionality, which acts as if the remote host were part of the enterprise's campus network.

However they are actually configured they are intrinsically set up to have an internetwork side and a remote side.  Logical access to the internetwork is made within the access server box.  The following diagram should help to illustrate this.



The following table lists the major CISCO products.  Subsequent tables list product lines from other sources.


Cisco Access Servers
Product Series


Cisco AS2500 Four models, each with some combination of eight or sixteen asynchronous ports, one or two synchronous serial ports, and one Ethernet or Token Ring interface.
Cisco AccessPath Up to 24 T1/E1/PRI trunk interfaces, supports Fast Ethernet, FDDI, ATM, Token Ring, 10BaseT, 10BaseFL.
Cisco AS5300 Series Universal Access Server Two models each with three slot chassis.  Between one and two Ethernet, Fast Ethernet ports and 8MB serial ports.  Up to 8 trunks of ISDN PRI/T1 or ISDN PRI/E1.  Channelized T1/E1.  Stackable.
Cisco AS5400 Universal Access Server Carrier class server, seven slot chassis, hot swappable cards.  Provides up to 14,112 ports.  Two Fast Ethernet ports, 2 8MB serial ports and T1, E1 or CT3 DS1 trunks.  Channelized T3 and 8 port CT1/CE1/PRI.  Stackable.
Cisco AS5800 Universal Access Server 14 slot chassis. 144 DSP based modems per card,  12 T1/E1 ports per card, hot swappable.  Up to 48 channelized T1/E1/PRI interfaces or up to two channelized T3 interfaces.



This information will be updated intermittently.   In addition, I will post some offerings from CISCO competitors while trying to focus on those with largest market share.  Any assistance in this will be greatly appreciated.