The Distribution Layer (DL) Upgrade Project will replace the Distribution Layer (DL) Switch(es) in close to 200 buildings across the Ann Arbor campus to enable the capability for any of these buildings to connect to the upgraded network at 2x100 Gbps or 4x100 Gbps for dual distribution layer (DL) switches. All buildings on campus that have a distribution layer (DL) router will be affected by this project. The complete list can be found on the Building Status page.
This is a required upgrade in order to connect the building to the new core network. This upgrade provides new and supported equipment; it increases the connection speeds to 100Gbps as well.
The proposal to upgrade all of the DL switches runs through October 2026. We will spread the work across fiscal years 2023 to 2027.
The project will replace the Distribution Layer (DL) Switch(es) in around 200 Ann Arbor campus buildings. There will be work that happens before the upgrade and after.
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Before:
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Verify the current location for the DL that supports the equipment
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Install new fiber connections to the building
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Install the new DL and connect it to the new core network
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Test the new DL
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During (day of cutover)
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Move access layer switches from the old DL to the new DL. The amount of time needed for this portion of the process will vary greatly and is dependent on the number of access layer switches in the building.
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We expect a rolling network outage for the duration of the cutover as access layer switches are moved from the old to the new DL. Typically this just takes a few minutes, but has taken much longer on a few occasions. You may want to plan to work remote on this day.
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Test the new network
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After:
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The old DL will be removed and the site will be cleaned up.
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DL replacement will require a scheduled outage in which all wired and WiFi network services to the building will be affected. The outage is typically seen as a rolling outage throughout the building as access layer switches are moved from the old to the new DL. Typically this just takes a few minutes, but has taken much longer on a few occasions.
We have prioritized building transitions based on the following data:
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The age of the existing DL determined the Initial prioritization.
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Known bandwidth bottlenecks and constraints
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Imminent research needs
Our prioritization approach will complete the DL upgrade work in as timely a manner as possible. Conversations with units will help clarify actual scheduling.
Refer to DL Upgrade Building Status for the complete list.
There will be no cost to replace the first DL. Units already funded the DL replacement through the backbone network charge. However, for buildings that have a second DL, the unit will be responsible to fund the replacement or removal of the second DL.
Your unit can put in a request to replace the second DL. As usual the unit will fund all capital charges associated with the second DL.
The unit will be responsible for all the charges associated with removing the second DL.
Visit Campus Building Network Connections to learn more about the U-M campus buildings DL connections.
Buildings that have been migrated to the new DL should request access to NetDash (SwitchConf) tool to configure ports on the new access switches. Training by ITS is required for all IT professionals requesting NetDash (SwitchConf) before access being granted.
Contact the Distribution Layer (DL) Upgrade Project team at [email protected]