Concepts

Clients and services

The router knows two kinds of subscriber.

Services are the current model. A service is one customer, one ONT, one speed, one fixed address and a permanent id (svc_xxxxxxxx). Your billing creates it with one call. The router registers the ONT on the OLT and sets up everything on its own side. No MAC address is ever needed: if the customer replaces the home router, the service keeps working with the same address.

Clients are the older, MAC-based model. A client is a MAC address with a fixed IP on a VLAN you created. The MikroTik-compatible MK-api listener works with clients. Clients stay fully supported for networks that need them.

	Service	Client
Identified by	ONT (port and ONT id, through Option 82)	MAC address
Created with	dtvsol service add, POST /services	dtvsol clients add, MK-api
VLAN	one per PON port, created for you	one you create
Speed enforced by	the OLT (CAR)	the router (tc HTB)
Suspension	the ONT is deactivated on the OLT, and the address blocked	the address is blocked on the router

One VLAN per PON port

Every router has its own S-VLAN on each OLT. Inside it, every PON port has its own C-VLAN:

C-VLAN = 100 + card × 16 + pon

Port 0/1/0 (card 1, PON 0) is VLAN 116. Port 0/0/3 is VLAN 103.

Each PON port gets its own /24 from the services’ IPv4 pool (svc_ipv4_pool in /opt/dtvsol/etc/config.php), and its own /64 when IPv6 is set up:

port network = pool + (C-VLAN − 100) × 256      VLAN 100 → 100.64.0.0/24
gateway      = .1                               VLAN 116 → 100.64.16.0/24
ONT address  = .2 + ONT id                      ONT 7    → 100.64.16.9

On the router the port’s interface is named v<svlan>.<cvlan>, for example v1000.116. You never allocate VLANs or addresses by hand: they follow from the OLT, the card, the port and the ONT id.

Several operators’ routers can share one OLT. Each router has its own S-VLAN on it.

Option 82

When an ONT asks for an address, the OLT adds DHCP Option 82 to the request: which port and which ONT it came from. The router gives the ONT’s fixed address only to a request whose Option 82 names that ONT. This is why a service needs no MAC address.

See what the router receives:

dtvsol option82

CGNAT port blocks

Subscribers usually have private addresses (for example from 100.64.0.0/10). CGNAT sends them out through a small pool of public addresses.

The router’s CGNAT is deterministic. Each public address is divided into fixed port blocks (2048 ports each by default, from ports 1024–65535). Each subscriber gets one block on one public address and keeps it. Every assignment and release is written to /opt/dtvsol/log/cgnat-mappings.log.

So there is no per-connection log to keep. To answer “who used XXX.XXX.XXX.70 port 40000 at that time”, look up the block:

dtvsol cgnat lookup XXX.XXX.XXX.70 40000

See CGNAT.

Saved configuration and versions

The whole configuration lives in one SQLite file, /opt/dtvsol/data/dtvsol.db. Clients, services, VLANs, OLTs, plans, the network and the rest are documents in it. Every change is one transaction.

Like a switch’s flash, you can keep versions:

dtvsol config save "before the new OLT"
dtvsol config versions
dtvsol config diff 12 running
dtvsol config restore 12 --yes

The daily backup saves a version by itself when the configuration changed. Documents are never edited by hand: use dtvsol config edit <name>, which checks the JSON and keeps a version first. See Backup and restore.

The 120-second rollback

A change to the router’s own network (ports, bonds, addresses on them, the default route) can cut you off. So it is applied with a safety net:

1. The netplan files are backed up and a configuration version is saved.
2. The new file is checked with netplan generate, then applied.
3. You have 120 seconds to confirm. Without a confirm, the old network is put back.

A change that would take away the address your SSH session, the API or the monitor uses is refused before anything runs.

dtvsol netcfg apply
dtvsol netcfg confirm      # keep it
dtvsol netcfg rollback     # or put the old one back now

The monitor’s Settings → Interfaces page works the same way. See Network changes.