ISP Support Ticket Template: ONT Port Negotiates at 100Mbps (Evidence Pack)

Last updated: 2026-01-02

Use this template when an ONT/router port negotiates 100 Mbps on one LAN port but 1 Gbps on another, even after changing cables/devices. It includes an evidence checklist and copy-paste commands.

Goal

Send a high-quality ISP ticket that:

clearly describes the issue
includes reproducible steps
attaches evidence (link speed + cables tested + ports tested)
requests the right action (ONT port profile/negotiation check or hardware swap)

1) Evidence checklist (fill this in)

Customer / Service

Account/Contract ID: [ ]
Service type: [FTTH / ONT model if known]
Location: [City, Area]

ONT / Port details

ONT model: [ ]
Firmware (if visible): [ ]
Problem port: LAN1 negotiates 100 Mbps
Working port: LAN2 negotiates 1 Gbps

Tests completed

Swapped cables: [Yes/No] (list cable types: Cat5e/Cat6)
Tried different device on LAN1: [Yes/No] (MikroTik, laptop, etc.)
Forced speed/duplex on client side (if possible): [Yes/No]
Power-cycled ONT: [Yes/No]
Factory reset ONT: [Yes/No] (only if allowed)

Impact

This port is required for [routed subnet / static /29 / business services]
Degraded service: [latency / stability / bandwidth]

2) Commands to capture proof (copy-paste)

2.1 MikroTik (RouterOS) — link negotiation proof

Replace etherX with the interface connected to ONT LAN1 / LAN2.

Also export interface settings (optional):

What you want in the screenshot/output:

rate: 100Mbps on LAN1 vs rate: 1Gbps on LAN2
full-duplex state
link-partner-advertising if shown

2.2 Windows (laptop/PC) — link speed proof

Optional advanced properties:

3) Copy-paste ticket text (EN)

Subject: ONT LAN1 port negotiates only 100Mbps while LAN2 negotiates 1Gbps (cables/devices tested)

Message:
Hello Support Team,

I’m experiencing a persistent link negotiation issue on my ONT.

ONT LAN1 always negotiates at 100 Mbps.
ONT LAN2 negotiates at 1 Gbps using the same router and the same cable type.
I tested multiple cables (Cat5e/Cat6) and multiple devices (router and PC). The result is consistent: LAN1 stays at 100 Mbps.

Reproduction steps:

Connect router/PC to ONT LAN1 → link speed shows 100 Mbps.
Move the same cable/device to ONT LAN2 → link speed shows 1 Gbps.
Swap cables/devices → LAN1 remains 100 Mbps.

Impact:
LAN1 is required for my routed subnet/business configuration. This limitation reduces performance and affects stability/latency.

Request:
Please check the ONT LAN1 port configuration/profile and auto-negotiation settings. If needed, please arrange a remote port reset/profile correction or ONT replacement.

Evidence attached:

Screenshots/outputs showing link speed on LAN1 vs LAN2 (MikroTik/Windows).

Thank you,
[Your Name]
[Account/Contract ID]
[Phone]

4) Verification after ISP action (what to re-test)

After they “reset profile” or replace ONT:

Re-run MikroTik monitor:

Re-run Windows:

Expected: LAN1 shows 1.0 Gbps (or higher if 2.5G exists), full duplex.

5) Rollback / safe fallback

If you must keep service running until fix:

Use LAN2 for gigabit and reroute config temporarily (document changes)
Keep a note of original cabling and port mapping for reverting after ONT fix

ISP Support Ticket Template: ONT LAN Port Negotiates at 100Mbps (Evidence Pack)