nixfiles/docs/sites/home/switches.md

Home switches

Reference for the two MikroTik switches on the home network — jim and dave — plus the Ubiquiti switch brian, and how the home boxes and the Digiweb WAN hang off them. These switches are not managed by this flake; they are configured by hand (RouterOS on jim/dave, UniFi on brian). It covers the physical topology, the VLAN map, and how the Digiweb WAN reaches river.

In short: the Digiweb ISP VLAN (10) is trunked straight through to river (which runs PPPoE on it), and the ONT's untagged management is PVID'd onto VLAN 140 at brian, its edge switch. VLAN 10 is carried untranslated because a single ONT makes it unique on the fabric — see the WAN path and why not translation. The router side lives in river.md; the logical network map in networking.md.

The switches

	jim	dave	brian
Identity	jim-sw	dave-sw	(UniFi)
Model	CRS326-24G-2S+	CRS504-4XQ	Ubiquiti 10GBASE-T
Switch chip	Marvell 98DX3236	Marvell 98DX4310 (+ Atheros 8227 for the 1G mgmt port)	—
OS	RouterOS 7.18	RouterOS 7.18	UniFi
Ports	24×1G + 2×SFP+	4×QSFP28 (100G, breakout-capable) + 1G mgmt	10GBASE-T
Bridge	main, vlan-filtering=yes	main, vlan-filtering=yes	UniFi VLAN profiles

jim and dave run a single hardware-offloaded bridge (main) with VLAN filtering. Access to the MikroTiks is SSH as admin / admin by short hostname (see Accessing the switches). Only jim and dave can do hardware VLAN translation (/interface ethernet switch rule on the Marvell chips); brian cannot rewrite tags, only trunk/PVID them.

Physical topology

The ONT terminates on brian; jim's wan-pon-in (sfp-sfpplus2) is a spare SFP+ port.

                                                  Virgin Media cable modem
                                                            │
                                                            │ (VLAN 130)
                                                            │ wan1/wan2/wan-in
       ┌──────────────────────────────────────────────────┴──┐
       │  jim   CRS326-24G-2S+  (Marvell 98DX3236)             │
       │  1G edge ports: castle, fort, pronter, laptop-dock,   │
       │  palace-kvm, ups, ether15-20, wan1/wan2/wan-in        │
       │  wan-pon-in (= sfp-sfpplus2)  ← spare SFP+            │
       └───────┬───────────────────────────────────┬─────────┘
   dave-uplink ┤ (= sfp-sfpplus1)                    │ stream, palace (1G secondaries)
       10G trunk│                                     └── stream (box, dual-homed)
       ┌─────────┴───────────────────────────────────────────────┐
       │  dave   CRS504-4XQ  (Marvell 98DX4310)                    │
       │  jim-downlink = qsfp28-3-1                                │
       └──┬───────────┬──────────┬───────────────────┬────────────┘
palace(100G)          │ castle   │ stream            │ brian-downlink
= qsfp28-1-1          │          │                   │ (802.3ad LAG: brian1+brian2)
     ┌────────────────┴─┐        …                   │
     │ palace host      │              Digiweb (PPPoE) via ONT
     │  └ river (VM)    │                       │
     └──────────────────┘                 ┌─────┴─────┐
   ↑ river's WAN + LAN ride the 100G link │    ONT    │ untagged mgmt 192.168.100.1
                                          └─────┬─────┘ + tagged VLAN 10 (ISP)
                                                │
                                       ┌────────┴────────┐
                                       │  brian (UniFi)  │  PVID 140 on the ONT port,
                                       │  10GBASE-T      │  tagged VLAN 10 allowed through
                                       └────────┬────────┘
                                                └── brian-downlink LAG up to dave

Notes:

• river runs as a VM on the palace host; its uplink is dave's 100G palace port. jim also has 1G palace/stream ports, but those are secondary links and do not carry the WAN.
• stream (the second router box) is dual-homed to both jim and dave (STP picks the active path).
• brian is a Ubiquiti 10GBASE-T switch, downlinked from dave over an 802.3ad LAG (brian-downlink = brian1 + brian2, layer-2 hash). It hosts the ONT.

VLANs

VLAN	Name	Purpose
— (native)	core	Switch management, 192.168.64.0/24 (jim .10, dave .11, brian .13)
100	hi	High-performance / jumbo network (MTU 9000)
110	lo	Standard LAN
120	untrusted	Guest / untrusted network
130	wan	stream's WAN — Virgin Media cable modem (untagged on jim's wan1/wan2/wan-in)
140	wan-pon-ont	ONT management, 192.168.100.0/24 (PVID'd at the ONT edge)
10	pon-isp	Digiweb ISP transport — trunked straight through to river, PPPoE runs on it
141	wan-pon-isp	Reserved — the translated ISP VLAN for the future multi-ONT design

Switch L3 presence (/interface vlan on main) exists only for VLANs the switch is managed from — hi (100) and lo (110), plus native core. WAN and guest VLANs deliberately have no switch L3 interface.

The Digiweb WAN path (trunked VLAN 10 + PVID 140)

The ONT presents two things on one wire:

• untagged management traffic (192.168.100.x), and
• tagged VLAN 10 carrying the Digiweb ISP session (the BRAS requires VLAN 10).

With a single ONT there's no reason to translate anything — VLAN 10 is unique on the fabric, so we just carry it end to end and let river run PPPoE directly on it:

1. Untagged mgmt → VLAN 140, at the ONT's edge switch (brian). brian sets the ONT port's PVID to 140 so the untagged management traffic becomes VLAN 140, and allows tagged VLAN 10 through the same port. river takes 192.168.100.100/24 on VLAN 140 (matching stream's modem-mgmt .100) to reach the ONT web UI at 192.168.100.1. Doing the PVID at the ONT-facing edge keeps it clean — the untagged frames never share a domain with anything else.

2. VLAN 10 (ISP) trunked straight through, untranslated. brian → dave → palace carry tagged VLAN 10 by ordinary bridge-VLAN membership. No /interface ethernet switch rule, no pinning, no asymmetric-learning issues — it's just a normal tagged VLAN. river attaches PPPoE to VLAN 10 directly (wan-pon-isp netdev = VLAN pon-isp = 10; baby-jumbo MTU 1508 so PPP nets a clean 1500).

Net result: river runs PPPoE single-tagged on VLAN 10 and holds a VLAN 140 address to reach the ONT. See nixos/boxes/home/palace/vms/river.nix for the river side.

ONT ──(untagged + VLAN10)── brian ──(VLAN140 + VLAN10)── dave ──(VLAN140 + VLAN10)── river
        ONT port             │ PVID140 + tagged 10        │ plain bridging
                             └─ brian-downlink LAG ── dave ┘

Why not translation (for one ONT)?

Translation would swap VLAN 10 → 141 with two pinned hardware ACL rules to keep VLAN 10 off the rest of the fabric. That buys nothing with a single ONT — VLAN 10 is already unique, so trunking it is simpler and rule-free. Translation only earns its keep when two ONTs both deliver VLAN 10 and would collide (below).

Switch configuration

How each switch is set up for the Digiweb WAN path. Confirm any change on the box before applying (see Accessing the switches).

brian (UniFi) — hosts the ONT:

• The ONT port has native/untagged network = VLAN 140 (PVID) and is a tagged member of VLAN 10, so the ONT's untagged management lands on 140 and its tagged ISP frames pass through.
• The brian-downlink LAG up to dave trunks tagged 140 + tagged 10 (alongside the LAN VLANs).

dave (RouterOS) — trunks both WAN-pon VLANs to brian-downlink and palace. The ISP VLAN 10 row:

/interface bridge vlan add bridge=main vlan-ids=10 tagged=brian-downlink,palace

VLAN 140 also spans brian-downlink,palace (it carries a few other members too). No switch rules — this is plain tagged bridging.

jim (RouterOS) — carries none of the Digiweb WAN path: no translation rules, and no VLAN 10/140/141 rows. wan-pon-in (sfp-sfpplus2) sits at pvid=1 as a spare port. jim only handles stream's VLAN-130 WAN and the LAN VLANs.

Future: multiple ONTs (per-port VLAN translation)

If a second ONT arrives (e.g. a Digiweb line for stream, or a second river), trunking breaks: both ONTs deliver tagged VLAN 10, and plain bridge-VLAN filtering can't tell them apart. That's when translation earns its place — a switch rule matches on the ingress port, so each ONT's VLAN 10 becomes a distinct fabric VLAN:

• ONT-A port: VLAN 10 → 141 (→ river)
• ONT-B port: VLAN 10 → 142 (→ stream / second river)
• mgmt: PVID each ONT port onto its own VLAN (140, 143, …) so both ONTs' 192.168.100.1 stay in separate L2/L3 domains.

The forward direction isolates naturally (each ONT maps to a different fabric VLAN). The return direction is where port targeting is mandatory: both translate back to VLAN 10, so bridge VLAN 10 now has two members and a plain FDB-miss flood would leak one ONT's upstream to the other. Each return must be pinned to its port with new-dst-ports:

# ONT-A: 141 in on palace → 10, forced out ONT-A's port
# ONT-B: 142 in on stream → 10, forced out ONT-B's port

Each ONT port must also be a tagged member of bridge VLAN 10 for correct egress tagging (the missing piece that otherwise shows up as pppd "Timeout waiting for PADO"). The pins bypass the FDB, so the two ISP sessions never mix.

Why a new switch: jim (the only box with spare SFP+ and the translation feature) has just one free SFP+ port, so it can't host two ONTs. The plan is a dedicated CRS305-1G-4S+ (4×SFP+, same Marvell rule support) to land multiple ONTs and do the per-port translation there, feeding distinct fabric VLANs up to dave.

Accessing the switches

The switches resolve by short hostname on the home network — the home routers serve their records in the home zone (nixos/boxes/home/routing-common/dns.nix: jim → hi .10, dave → hi .11, brian → core .13). From a box on the home network just ssh admin@jim / admin@dave. Non-interactive pattern (password auth, avoids the ssh-agent hang):

sshpass -p admin ssh -o IdentityAgent=none -o PubkeyAuthentication=no \
  -o PreferredAuthentications=password -o StrictHostKeyChecking=accept-new \
  -o UserKnownHostsFile=/tmp/sw_known_hosts admin@jim

Always confirm config changes on the switch (print the affected menu, apply, re-verify). brian is UniFi — configured through its controller, not RouterOS CLI.

Management IPs

	core (192.168.64.0/24)	hi (192.168.68.0/22)	lo (192.168.72.0/21)
jim	.10 (on main)	.10	.10
dave	.11 (on management, the 1G Atheros port)	.11	.11
brian	.13 (core)	—	—