CMTS Router

• Cisco ubr7246 at NOC

IP addressing scheme

• CMTS system 10.16.0.0/16 statically routed to gi0/1 10.254.0.65/29
• Cable modems DHCP from router - 10.16.254.X/24
• Node routers - 10.16.0[node]/24
• Access points - 10.16.[node]0.[AP]/24
• Subnets to customers 10.16.[node][class].x/24 gateway .254

Examples:

cable modem at node 1 - 10.16.254.X

Node 3 Edgerouter - 10.16.0.3. ( login with user 'admin' not root )

Access point cap2-3 - 10.16.20.3

Vendor network from node 3 - 10.16.36.x/24 - DHCP from node Edgerouter

Routing

Each node router is a BGP neighbor to CMTS. Its routes are learned by CMTS via BGP over the 10.16.0.0/24 subnet.

Cable modems are transparent bridges - not involved in the routing scheme.

Outside plant

Diplexer at NOC combines low frequency upstream (from field to Internet) and high frequency downstream (from Internet to field) to single cable feed towards Main Camp. No power on this segment.

Power injector at Main Camp supplies 90VAC towards nodes.

Splitter at Main Camp feeds two cables to field with power. One cable to Ho Gate at Xavanadu (Node 1) via Security Tower (Node 4).

Second cable to Node 2 (behind booth L00) and Node 3 (behind booth L43)

At each node is a directional tap that splits a small portion of the signal to the node and passes the remainder through to additional nodes on that segment. Nodes 2 and 4 feed nodes 3 and 1 respectively. Fuses inside each directional tap determine whether power is passed to the through port and/or tap port. Taps at the end of the line have their through ports terminated. Taps have a fixed dB loss to the tap port.

Node 4 at the Security Tower has grid power and is not powered via the cable. It has one AP attached at Wind Gate and is also used to feed wired Ethernet to security tower, Little wing, and KOCF.

Node	Location	DB loss	Tap power	Thru power	Tap feed	Thru feed
1	Behind Ho Gate	12	Yes	No	Node 1	75 Ω Term
2	Behind booth L00	16	Yes	Yes	Node 2	Node 3
3	Behind booth L34	16	Yes	No	Node 3	75 Ω Term
4	Security Tower	16	No	Yes	Node 4	Node 1

Note that the directional taps, power injector, and splitters should have silicone grease applied to the gasket and fitting O-rings to prevent water intrusion.

Access points

All are standard Rocket M5. All APs on a node share the same subnet and users can roam between access points within a node without losing their IP. Subnets are all /24. Assign RF channels outside of the DFS band. Use different RF channels for APs in close proximity.

Node box BOM

Description	MFG	Part No.	Source	Price (7/1/25)
Enclosure	Hammond	PJ14126	Mouser	$166.88
Panel	Hammond	14R1311	Mouser	$19.17
Transformer	Triad	F7-36	onlinecomponents	$18.04
Transformer(alt)	Triad	FD7-36	Mouser	$21.93
Fuseholder	Eaton	BK2-S-4201-1-R	Mouser	$1.28
Power Inserter	Antronix	ARPI-2000	TelExpress	$2.99
Cable modem	Cisco	DPC3010	Amazon	$33.99
Router	Ubiquiti	ER-X-SFP	Amazon	$109.00
Outlet	Eaton	78B-BOX	Lowes	$3.83

Please do not make substitutions without checking with Jay.

-- JayH - 26 Jun 2023