DCD Design Note 139.0

 

D0 DAB Offline Network

 

 

 

 

 

Darryl Wohlt

 

June 11, 1999

 

 

 

 

Abstract: This Design Note describes the proposed network implementation for the D0 Offline network. A Cisco Catalyst 6509 is proposed for connection of all 10/100Mbps and 1Gbps systems and links. Six Catalyst 2948Gs, each linked to the 6509 at 1Gbps, would be used for 10/100Mbps connections in the three Trailer clusters. Systems in DAB3E, DAB5 and DAB6 would be connected to small hubs each linked at 100Mbps to the 6509. Systems in DAB1-3 within Category-5 UTP distance would be accommodated by up to 48 10/100TX ports in the 6509.

 

DAB D0 Offline Components

The D0 Offline systems are located in the following areas:

    1. DAB6 Offices, 60-120 nodes, 49 heard;
    2. DAB5 Offices, 60-120 nodes, 47 heard;
    3. DAB3E Offices, 36-72 nodes, 14 heard;
    4. DAB3W Offices, 16-32 nodes, 4 heard;
    5. DAB2 Offices, 12-24 nodes, 4 heard;
    6. DAB1 Offices, 6-12 nodes, 9 heard;
    7. Trailer City West (TCW), 96-192 nodes, 70 heard;
    8. Trailer City North (TCN), 64-128 nodes, 54 heard;
    9. Trailer City East, 128-256 nodes, 90 heard.

The quantity estimates above ("x-y nodes") reflect a probable number of connections per outlet box (x) and the maximum possible number of connections per outlet box (y). A recent survey using observed traffic revealed the "heard" counts shown.

DAB D0 Offline Switch Port and Aggregate Throughput Requirements

The central switch port allocations and estimated maximum data rates for the DAB D0 Offline components are as follows:

 

Proposed DAB D0 Offline Network

A single-chassis high performance switch would be placed in the DAB2 Computer Room, augmented with a structured wiring system (Design Note 127) capable of delivering 10/100/1000Mbps to each computing node or satellite switch. Six satellite switches with high bandwidth uplinks to the main switch would be located in the west, north and east trailers. All nodes in the component categories listed above, except for the offices in DAB3E, 5 and 6, would connect to dedicated ports in these switches. With one possible caveat, the switch backplanes will have more than enough bandwidth to provide a non-blocking switch fabric for all traffic between the connected ports.

The main DAB D0 Offline switch will be a Cisco Catalyst 6509 9-slot chassis with dual redundant power supplies. The 6509 has a 32Gbps backplane and 8 slots available for interface modules, the ninth being reserved for the supervisor module. The interface modules available to date include an 8-port Gigabit Ethernet module, a 24-port fiber-based Fast Ethernet (100BaseFX) module (MT-RJ style connectors), and two versions of a 48-port 10/100BaseTX module (one with RJ45 connectors, another with telco style RJ21 connectors). A 16-port Gigabit Ethernet module is forthcoming. The requisite supervisor module comes with two 1Gbps port slots. All gigabit port slots on any module are configurable for short-haul (1000BaseSX) fiber or long-haul (1000BaseLX) fiber using replaceable GBIC inserts.

Initially, the 6509 will be configured with an 8-port gigabit ethernet module, a 24-port 100BaseFX (MT-RJ) module, and two 48-port 10/100 (RJ45) ethernet modules. Two additional gigabit ethernet ports will be afforded by the Supervisor module. One 1000BaseLX and six 1000BaseSX GBICs will be installed in the 6509’s gigabit ports.

The offices on the 6th, 5th, and 3rd (east) floors of DAB are beyond the 100m distance limit for Category-5 copper wiring and will be served by several 16-port 10/100 hubs connected to the 6509 over 100BaseFX links (see Design Note 127) . One 24-port 100BaseFX module will accommodate these links. It is notable that these office systems will be using shared LAN environments, each LAN limited to 15 nodes or less. Should the available bandwidth become inadequate, the probable remedy would be to move individual high-bandwidth nodes to dedicated 100BaseFX links into the 6509. Other remedies might include adding hubs and dispersing the nodes to fewer per hub, and/or replacing hubs with 10/100 switches, using 100Mbps or 1Gbps uplinks into the 6509.

The offices on the 3rd (west), 2nd, and 1st floors of DAB are within the 100m limit and will be wired directly to 10/100BaseTX ports on the 6509. Two 48-port 10/100 modules would be required to satisfy the maximum port requirement, however initially only one module needs to be ordered to meet current needs.

Connections in the three trailer clusters will be served by a pair of Cisco 2948G fixed-configuration switches in each trailer cluster. Each switch will have its own 1Gbps uplink to the central 6509 in DAB.

 

 

Procurement

The proposed initial procurement breakdown is shown below.

Implementation

The new Catalyst 6509 and 2948Gs for DAB D0 Offline would be installed within 30 days of delivery and made available for the various test scheduled as part of the preparations for Run-II computing support. Complete installation of the structured cabling system described in Design Note 127 will be required for full realization of this implementation.