Network Architecture

Network Architecture

Data Centers

We are a global messaging service with data centers in the U.S. located in Bridgeton, Missouri and Middletown, Virginia.

Bridgeton, MO consists of 2 Datakits (SX and SY) which connect the 5 Phoenix nodes, 9 Stratus nodes, and a customer test node. There are also 2 SMTP nodes and an Operations node (Stratus Polo) located in Bridgeton.

Middletown, VA consists of 2 Datakits (MX and MY) which connect the 5 Phoenix nodes, the old OPS node, and 4 Stratus nodes.

The International Data Centers are located in Sydney Australia, Toronto Canada, Tel Aviv Israel, and London England. These data centers have their own Customer Assistance Center for customer interface. However, it is the responsibility of the NOC to monitor these nodes, react to alarms, and interface with the technicians at these sites to resolve problems.

Access to Attmail is worldwide through one of our data centers. This access can be dial-up, leased line access, X.25, frame relay, or TCP/IP. The two data centers residing in Bridgeton and Middletown have two datakits each. These datakits know all of the datakits at the international locations and have circuits to each one. These datakits carry most of the traffic from one data center to the other. Some of the international sites have circuits to other data centers in their area, but the most common path is to route through circuits in either Bridgeton or Middletown.

Node Configuration

Each GMS node consists of either one Stratus Computer or three AT&T 3B2 Phoenix Computers. The phoenix processor is a 3B2/1100 with mips r3000 RISC processor on the system board. These three machines run the GMS network software (UNIX SVR4 based) and are where the customer accounts reside on disk areas referred to as customer file systems. The machines share their external hard disks in a special mirrored configuration to allow customer file systems to be moved from the primary processor to the alternate processor in cases of hardware/software failures or to assist in load balancing. This minimizes the customer down time. The Stratus is a fault tolerant computer based on the HP PA-RISC HP7100 microprocessor. They can be either 1200 series (12 slot backplane) or 600 series (6 slot backplane).

All nodes share basic configuration traits. Differences occur depending on what services are provided. A node can be either a standard email node, a shared data provider node, or an inbound or outbound fax node. The standard email node has 11 customer file systems mounted. The standard configuration for the Phoenix node is the 05000, 10000, 15000, and 20000 file systems mounted on the A processor, the 25000, 30000, 35000, and 40000 file systems mounted on the B processor, and the 45000, 50000, 55000 file systems mounted on the C processor.

A shared data node has only 9 customer file systems and 3 shared data file systems, with each processor having 3 customer file systems and 1 shared data file system mounted. These file systems continuously update shared folder information and are linked to other processors to allow access to shared data by accounts across the network.

A fax node runs a process called Remote File Sharing (RFS) and has only 6 customer file systems and 6 remote spool file systems used for fax deliveries. The standard configuration is 2 customer file systems and 2 remote spools mounted on each machine.

Most all of the international nodes are both EMAIL and EFAX capable, and at least one node per site provides shared data.

Other network components consist of Datakits, trunks, fax feps, sync feps, G2's, and AUI adapters. Each of these will be discussed in further detail later in this document.

Datakits - network switches that tie all the parts of the network together by providing a means of connecting different types of equipment. The Datakits provide links between service nodes in each data center, connect the T1's between data centers, and equipment that is shared by nodes, such as outbound modems.
Trunks - We use a variety of fiber trunks to connect the datakits together. The T1's form the backbone of the network, running between the datakits.
Fax Feps - 6386 PC's used as front end processors that contain fax boards for submission and delivery of G3 faxes, and voice cards (inbound) that provide user interface. There are some 486's that are used as SSD feps for inbound fax guest access via customer specific 800 numbers.
Sync Feps - We use 3B2's, 6386's, 6486's, and Sun Ultra Enterprise servers to provide network access for large computer systems (mainframe) at high speeds. The traffic volume of some of these customers warrants dedicated line access into the network.
G2's - The G2's are switches that connect telephone access into the network's modems and fax feps.
AUI Adapters - Starlan adapter that connects to an NAU board within the Phoenix processor to provide TCP/IP connectivity between the node and a router.

Network Access

X.25

Customers are able to dial a local access number to a packet service using the CCITT X.25 protocol, and then connect to attmail through this asynchronous dial-up method. These communications come in from AT&T Accunet Packet Service (APS) and other X.25 provider companies. The X.25 circuits are interconnected to either the datakits or the firewall routers, depending on the type of communications. This access method is mainly used by X.400 accounts and Federal government users. More information on X.25 can be found in OPSDOC Vol. 5, Proc. B-01 and B-02.

GMSNET

Provides TCP/IP access to the GMS network. GMSNET also has the fax fep ethernet traffic on it. It has firewall routers that allow customer access to the SMTP agents on GMS. The firewall routers are connected to frame relay services, X.25 service, and other leased line connections. This is not a part of the PTNII network, but a separate and connected network.

The main function of GMSNET is to provide interprocessor communications that are now carried on datakits, and message services over TCP/IP connections. It is partitioned off into several segments by backbone routers made by Wellfleet. The backbone routers to the GMSNET are BGT04BN and BGT05BN in Bridgeton, and MDT04BN and MDT05BN in Middletown. The international sites use a smaller router for the same functions at their sites. They connect via frame relay through the Datakits to connect to Bridgeton and Middletown. The different segments on this lan are connected to hubs in ODS rack mount cabinets. The hubs are where all the lan cables are connected, from all of the GMS node processors, fax feps, and routers. Each hub can support up to 4 segments. The different segments partition the network so all of the communications will not be on the lan at one time.

Megacom / G2's

Dial-up 800 number access. The G2 routes inbound fax calls to inbound fax feps to be answered by DD4 fax board (4 ports) and voice power (VP) card, instead of modem pools. Megacom also routes our dial up sync customers to us via our Telenex switch, where they are then routed to sync feps for message processing.

Access number for Efax: 800-232-9674

PTNII

The PTNII network is an access only ethernet network. It was designed to allow access to the GMS accounts and to bypass Megacom routing. PTNII allows 800 number dial-up access calls to be taken as a different type of call on a WATS line that is cheaper. The customer still dials the 800 number, but the access is actually local. This network was created to decrease access per minute costs. The PTNII call is originally directed to an edge vehicle, which is a silicon graphics computer that controls a bank of modems. The edge vehicle tells the modem to answer the call, prompts the caller for their username and password. A query is made to DNS to determine the customer's home node using the Customer Directory (CD). The call is then routed via IP, where the username and password are validated using the auth process.

IP traffic is routed directly to the firewall routers (Cisco), then on to the GMSNET routers (Wellfleet). The PTNII network is also used as the Internet backbone for dial access to AT&T Worldnet service.

Synchronous

Access to the network is set up by the sync engineering group. This may be a lease line or dial-up into a hunt group. We will also dial back out to customers via these lines. Inbound calls are routed to sync feps, which are designated to a node on the GMS network for message routing via Message Transport (MT). Sync is a customer specific application and each customer has their own unique configuration.

EditText of this page (last modified 2005-11-16 10:45:10)
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