Bay Area Backbone

The goal of the Bay Area Backbone Project is to build a solid, fast, network between high sites in the Bay Area. This network will be available to support various amateur radio projects. The Bay Area Mesh is one of those supported projects.

Organizations

ARIN

SFWEM is registered with the American Registry for Internet Number (ARIN)

IPv4

The backbone operates using two sets of IPv4 addresses:

• 100.100.0.0/16 - These network address are available within the Backbone, but are not routed externally.
• 206.197.44.0/24 - These network addresses are routed within the Backbone and are also accessible from the Internet.

IPv6

The backbone operate using one set of IPv6 addresses:

• 2620:B8:A000::/48 - These network address are routed within the Backbone and are also accessible from the Internet.

Backbone Network Structure

Physical

Radios

A minimal backbone endpoint consists of two radios providing a point-to-point link between two sites. Generally Ubiquiti airFiber 5XHD radios are used. In some cases a point-to-multipoint setup is used (generally where tower space is limited). In these cases we use the Ubiquiti LTU-Rocket to provide the multipoint target, with 5XHD radios (with alternate firmware) at the other ends.

Routers

Any router capable of supporting OSPF can be used to support the radios. Two options currently deployed are the Ubiquiti EdgeRouterX and the Mikrotik CRS112-8P-4S.

Software

The backbone network runs OSPF. Detailed information on the configuration can be found here.

Backbone Links

Active

• Fish Ranch
  • ORCA
  • San Bruno Mountain (Building 7)
• ORCA
  • Fish Ranch
  • Wolfback
• CCCC
  • Mount Diablo
  • Richmond Field Station
• San Bruno Mountain (Building 7)
  • Fish Ranch
  • San Carlos
  • Swallow
• San Carlos
  • San Bruno Mountain (Building 7)
  • Sunol Ridge
• Sunol Ridge
  • San Carlos
• Swallow
  • San Bruno Mountain (Building 7)
• Mount Diablo
  • CCCC
• Richmond Field Station
  • CCCC
• Wolfback
  • ORCA
  • Oxford
• Oxford
  • Wolfback

Planned

• San Bruno Mountain (Building 7)
  • Fire Station 8
• Fire Station 8
  • Mount Allison

Proposed

• Fish Ranch
  • San Bruno Mountain (Building 4)
• Sunol Ridge
  • Mount Allison
• CCCC
  • San Pedro
  • Wolfback

History

The first backbone link, between Fish Ranch and San Bruno Mountain, was installed on the 23rd November, 2021 and became operational on 3rd September, 2022. The goal was to provide a solid connection across the Bay which the AREDN network could use. It had been observed by the AREDN network builders in Southern California, that a better quality and more stable network could be constructed by creating a solid, well engineered backbone, to which local community AREDN networks could connect.

Bay Area Mesh on the Backbone

Using the Bay Area Backbone to support the Bay Area Mesh has a number of advantages for the Mesh:

• It easier to connect high sites to other high sites, especially when we're trying to connect different neighborhoods while avoiding mountain ridges.
• High sites are often backed up with generator power. We provide battery backup ourselves, but that will only last so long.
• High sites will be there when the Ham moves on. Because these are generally commercial sites with long histories of ham involvement, we are not a the whims of someones current housing situation or - in some cases - employment situation.
• It's often easier for a neighborhood to connect up to a high site (or more than one) as they're less obstructed.

Status

The current health of the backbone is monitored here (internet)

Hardware

The mesh operates on the Backbone by creating point-to-point VLANs between mesh sites (these are called xlinks - see below). Mikrotik hAP ac2 nodes provide the the mesh endpoint hardware. The VLANs are passed across specific backbone links and traffic is not flooded across the backbone.

XLINKS

XLINKS are custom VLANs between sites which feed directly into the AREDN router. Think of them as DtD links, but only point-to-point.

Link	VLAN	A	B	Notes
San Bruno Mountain to Swallow	10	100.64.0.21	100.64.0.22
ORCA to Wolfback	11	100.64.0.17	100.64.0.18
ORCA to Fish Ranch	12	100.64.0.13	100.64.0.14
Fish Ranch to San Bruno Mountain (7)	13	100.64.0.10	100.64.0.9
San Carlos to Sunol Ridge	14	100.64.0.6	100.64.0.5
San Bruno Mountain to San Carlos	15	100.64.0.1	100.64.0.2
San Bruno Mountain to Fire Station 8	16	100.64.0.25	100.64.0.26
Fire Station 8 to Mount Allison	17	100.64.0.29	100.64.0.30	Subject to change as site uses VLANs extensively
Oxford to Wolfback	18	100.64.0.33	100.64.0.34
Fish Ranch to San Bruno Mountain (4)	19	100.64.0.37	100.64.0.38
San Bruno Mountain (7) to Black Mountain	20

Backbone links appear in the mesh labeled as xlink but are no different from any other link in the network. We are not building a hierarchy with the backbone at the top and the rest of the mesh hanging below. But the nature of the backbone, how it connects, and the way the mesh routing protocol operates, these links will provide preferred pathways between physically distance locations.