🚀 Enable 10G Port

This guide walks through enabling 10 Gigabit Ethernet (10G) ports on VSOL OLT devices. By default, VSOL OLT ports operate at 1G (1 Gigabit); this procedure upgrades designated ports to 10G capability using debug mode CLI commands.

info

What you're doing: Accessing OLT debug mode and reconfiguring SFP+ port mode to support 10 Gigabit line rates instead of standard 1 Gigabit.

• Access OLT via Telnet or serial console
• Enter privileged and debug mode
• Configure GIU (Gigabit Interface Unit) to SFP+ mode (10G)
• Save configuration persistently
• Verify 10G port status
• Test bandwidth utilization

warning

Important Caveats:

• Debug mode is restricted—only authorized administrators should access
• Port reconfiguration requires OLT reload/reboot to fully apply (some models)
• Existing 1G connections on target port will be reset during mode switch
• Ensure SFP+ transceiver is 10G-capable and properly seated before enabling
• 10G line rates require quality fiber (typically OS2 single-mode) and low-loss connections
• Not all VSOL OLT models support 10G—check hardware specifications first
• Configuration persists after reload; reverting requires explicit reconfiguration
• Debug mode commands are undocumented—use cautiously

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Prerequisites

✅ VSOL OLT with SFP+ port(s) (hardware must support 10G)
✅ SSH or serial console access to OLT with root/admin credentials
✅ OLT running firmware v2.0 or later (most VSOL v2.x models support 10G)
✅ SFP+ transceiver module installed in target port (10G-capable, not 1G-only)
✅ Fiber optic cable (OS2 single-mode recommended for 10G distances)
✅ Upstream device port capable of 10G line rate (router uplink, aggregate switch, etc.)
✅ Understanding of OLT CLI mode progression (user → enable → config → debug-mode)
✅ Backup of current OLT configuration before making changes

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Configuration Steps

Step 1: Connect to OLT

Access the OLT via SSH or serial console (115200 baud, 8N1):

Option A: SSH Access

ssh admin@192.168.8.1
Password: [enter password]
OLT>

Option B: Serial Console

Connect serial cable to OLT console port (DB-9 or USB)
Open terminal (PuTTY, minicom, or Device Manager)
Settings: 115200 baud, 8 data bits, 1 stop bit, no parity, no flow control
Power on OLT and wait for login prompt
Login: admin
Password: [enter password]
OLT>

You should see the OLT> prompt, indicating you're in user mode.

Step 2: Enter Enable Mode

Escalate to privileged (enable) mode:

OLT>enable
OLT#

The prompt changes from > to #, confirming you're now in enable mode with full privileges.

Step 3: Enter Configuration Terminal

Access global configuration mode:

OLT#configure terminal
OLT(config)#

The prompt now shows (config), indicating you're in configuration context.

Step 4: Enter Debug Mode

Switch to debug mode (restricted, undocumented functionality):

OLT(config)#debug mode
OLT(debug-mode)#

warning

Debug mode warning: This mode is intended for support personnel only. Improper use can render OLT inoperable. Proceed only if you understand the implications.

Step 5: Configure GIU to SFP+ Mode (10G)

Set the Gigabit Interface Unit to SFP+ 10G mode:

OLT(debug-mode)#set giu mode sfp+
Setting GIU mode to SFP+ (10G)...
[OK]

Command breakdown:

• set giu mode = Configure Gigabit Interface Unit mode
• sfp+ = SFP+ standard (10 Gigabit capable)
• Alternative modes (if supported): sfp (1G), rj45giga (1G RJ45), rj45combo (1G RJ45 with combo port)

Expected output: [OK] or Setting completed

If you see [ERROR] Mode not supported, your OLT hardware doesn't support 10G, or the transceiver is incompatible.

Step 6: Exit Debug Mode

Return to configuration mode:

OLT(debug-mode)#exit
OLT(config)#

The prompt returns to (config).

Step 7: Save Configuration

Write configuration to persistent storage:

OLT(config)#write
Saving configuration...
[OK] Configuration saved to flash

Critical step: The write command saves changes to NVRAM/flash storage so they survive OLT reboot. Without this, changes are lost on next power cycle.

Expected output indicates successful save. If you see [ERROR] Write failed, check flash storage space: show flash-info

Step 8: Verify SFP+ Port Status

Exit configuration and check port status:

OLT(config)#exit
OLT#show interface

Expected output (example for SFP+ port):

Port      Status    Mode      Speed       IP Address
GE0/0/0   UP        SFP+      10Gbps      192.168.1.100
GE0/0/1   UP        SFP+      10Gbps      192.168.1.101
GE0/1/0   UP        SFPX      1Gbps       [disabled]

Key indicators:

• Mode: Should show SFP+ (not SFPX or RJ45)
• Speed: Should show 10Gbps (not 1Gbps or Auto)
• Status: Should show UP (if transceiver and cable are connected)

If status is DOWN:

• Verify transceiver is fully inserted
• Check fiber optic cable for kinks, dust, or contamination
• Test with known working 10G transceiver
• Reload OLT: reload

Step 9: Reload OLT (If Required)

Some VSOL OLT models require restart to fully apply 10G mode:

OLT#reload
Are you sure you want to reload? (yes/no): yes
Rebooting system...
System will restart momentarily
Connection closed

Wait 2-3 minutes for OLT to boot:

VSOL OLT Boot...
[OK] System started
OLT#

Reconnect and verify 10G status again (repeat Step 8).

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Understanding 10G Port Configuration

SFP+ vs SFP vs RJ45 Comparison

Interface Type	Standard	Speed	Transceiver	Fiber Type	Distance
SFP+ (10G)	IEEE 802.3ae	10 Gbps	SFP+ module (small optics)	Single-mode, Multi-mode	10-80 km
SFP (1G)	IEEE 802.3z	1 Gbps	SFP module	Single-mode, Multi-mode	2-70 km
RJ45 (1G)	IEEE 802.3u	1 Gbps	Copper (no transceiver)	Cat5e/Cat6 twisted pair	100 m
SFPX (Combo)	Mixed	Auto 1G	Auto-sensing	Fiber OR copper	Varies

VSOL OLT with SFP+ default mode: By default, SFP+ ports run in "compatibility mode" at 1G to support both 1G and 10G transceivers. The set giu mode sfp+ command explicitly locks the port to 10G-only, negotiating faster line rates.

Architecture Diagram

┌──────────────────────────────────┐
│     VSOL OLT Device              │
│                                  │
│  ┌──────────────────────────────┐│
│  │ Port Configuration:          ││
│  │ ┌─ GE0/0/0: SFP (1G) default││
│  │ ├─ GE0/0/1: SFP (1G)        ││
│  │ ├─ GE0/1/0: RJ45 (1G)       ││
│  │ └─ Uplink: SFP+ ← Set to 10G││
│  └──────────────────────────────┘│
│           │                       │
│     After: set giu mode sfp+      │
│           ↓                       │
│  ┌──────────────────────────────┐│
│  │ Uplink Port: SFP+ (10G)      ││
│  │ ├─ Speed: 10 Gbps            ││
│  │ ├─ Transceiver: SFP+ 10G     ││
│  │ └─ Distance: up to 40 km      ││
│  └──────────────────────────────┘│
│           │                       │
│     Fiber Connection              │
│           ↓                       │
├──────────────────────────────────┤
│   Upstream Device (10G Switch)   │
│   Port in 10G mode               │
└──────────────────────────────────┘

GIU Mode Lifecycle

Step	Mode	Prompt	Action
1	User	OLT>	Initial login state
2	Enable	OLT#	Enter enable
3	Config	OLT(config)#	Enter configure terminal
4	Debug	OLT(debug-mode)#	Enter debug mode
5	Config GIU	OLT(debug-mode)#	Execute set giu mode sfp+
6	Config	OLT(config)#	Exit debug with exit
7	Enable	OLT#	Exit config with exit
8	User	OLT>	Exit enable with disable

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Verification Steps

1. Check Port Speed After Configuration

Verify port now reports 10G capability:

OLT#show interface GE0/0/0
Interface: GE0/0/0
Mode: SFP+
Speed: 10Gbps
Status: UP
MTU: 1500

If speed shows 1Gbps, reload OLT: reload

2. Check Transceiver Information

Verify SFP+ transceiver is detected:

OLT#show transceiver GE0/0/0
Transceiver Information:
  Type: SFP+
  Vendor: VSOL (or compatible)
  Model: VSP-SFP10G-SR (example)
  Serial: SN123456789
  RX Power: -2.5 dBm
  TX Power: 0.1 dBm
  Temperature: 35°C

Expected values:

• RX Power: -3 to 0 dBm (stronger signal = closer transceiver)
• TX Power: -1 to +5 dBm
• Temperature: 0-70°C (within operating range)

If RX Power < -8 dBm or TX Power < -10 dBm, connection is degraded—check fiber for dirt/kinks.

3. Test 10G Link with Upstream Device

From upstream device (10G switch/router), verify 10G negotiation:

Router#show interface GigabitEthernet0/0/0
GigabitEthernet0/0/0 is up, line protocol is up
  Hardware is SFP+, address is 0000.1111.2222
  MTU 1500 bytes, BW 10000000 Kbit/sec (10 Gbps)
  Encapsulation ARPA, loopback not set
  Full duplex, 10Gb/s
  [GOOD - 10G link up]

4. Run Throughput Test (iperf)

Test actual 10G bandwidth utilization from OLT or connected device:

# On uplink device (originator)
iperf -c <OLT-uplink-IP> -P 4 -t 30 -R
# Expected: ~9-10 Gbps (accounting for protocol overhead)

# Example output:
[ ID] Interval           Transfer     Bitrate
[  1] 0.0-10.0 sec  11.5 GBytes  9.87 Gbps
[  2] 0.0-10.0 sec  11.6 GBytes  9.93 Gbps
[  3] 0.0-10.0 sec  11.4 GBytes  9.81 Gbps
[  4] 0.0-10.0 sec  11.5 GBytes  9.89 Gbps

If throughput is < 5 Gbps:

• Check for fiber contamination (clean connectors with isopropyl alcohol and lens paper)
• Verify SFP+ transceiver supports 10G (check model number)
• Test with different fiber patch cable
• Check for duplex mismatch on upstream device

5. Verify Configuration Persists After Reload

Reload OLT and verify 10G mode remains:

OLT#reload
[After reboot, reconnect...]
OLT#show interface
Port    Status    Mode     Speed
GE0/0/0 UP        SFP+     10Gbps  ← ✅ Persisted

If speed reverts to 1Gbps, configuration wasn't saved—repeat Step 7 (write).

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Troubleshooting

Issue	Cause	Solution
Port shows 1Gbps after set command	OLT requires reload to apply 10G mode	Run reload and wait 3 minutes; verify with show interface
Port status DOWN after 10G enable	Incompatible or failed transceiver	Verify SFP+ 10G transceiver is installed (not 1G SFP); check LED indicators
RX Power < -8 dBm (very weak signal)	Optical signal loss—dirty fiber or bad connector	Clean fiber connectors (isopropyl alcohol); inspect for cracks; replace fiber patch cable
TX Power off/unavailable	Transceiver TX failure or unsupported	Swap with known working 10G SFP+ module; verify vendor matches
Cannot enter debug mode	User permissions insufficient or debug disabled	Confirm you're using admin account; check if debug mode is restricted in firmware
"[ERROR] Mode not supported"	Hardware doesn't support 10G or SFP+ port doesn't exist	Check OLT model specifications; not all VSOL models support 10G; use different OLT model
Port goes UP/DOWN intermittently	Loose transceiver or dusty connector	Reseat SFP+ transceiver firmly; clean both ends of fiber patch cable
Speed negotiates at 1Gbps with 10G transceiver	Port still in auto-negotiation mode	Verify GIU mode change took effect: show interface should show SFP+; reload if needed
Cannot save config (write failed)	Insufficient flash storage on OLT	Check: show flash-info; delete old logs or backups; ensure 20MB+ free space
Upstream device won't recognize 10G link	Transceiver incompatibility or firmware mismatch	Verify transceiver vendor (VSOL, Broadcom, etc.) matches expectations; test with known working module
Performance drops after enabling 10G	CRC errors or frame loss due to optical issues	Run show interface counters to check error rates; clean fiber immediately
Debug mode exits unexpectedly	Session timeout or authentication loss	Reconnect and re-enter: enable → configure terminal → debug mode

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Advanced Options

Option A: Downgrade Port to 1G (Revert 10G)

If 10G causes issues, revert to 1G mode:

OLT(config)#debug mode
OLT(debug-mode)#set giu mode sfp
OLT(debug-mode)#exit
OLT(config)#write
OLT(config)#exit
OLT#reload

After reload, verify: show interface GE0/0/0 should show 1Gbps

Option B: Configure Multiple 10G Ports

Enable 10G on secondary SFP+ ports:

OLT(config)#debug mode
OLT(debug-mode)#set giu mode sfp+
OLT(debug-mode)#show interface | include GE0/0
# Lists all available GE ports
# Configure each SFP+ port in sequence
OLT(debug-mode)#exit
OLT(config)#write

Note: Most VSOL OLTs have 1-2 10G-capable ports (uplink ports). Standard PON/GE ports (1G) cannot be internally upgraded to 10G.

Option C: Monitor Real-Time Port Statistics

Check live port statistics during traffic:

OLT#monitor interface GE0/0/0
Interface: GE0/0/0 (SFP+)
In:  94.2 Mbps (1250 pps)  Out: 98.5 Mbps (1350 pps)
RX Errors: 0    TX Errors: 0    CRC: 0
Updates every 5 seconds (Press Q to exit)

Healthy indicators:

• Sustained 8-10 Gbps in/out during full throughput
• Zero CRC errors
• Zero RX/TX errors

Option D: Enable Jumbo Frames (9000 MTU) for Enhanced Throughput

Maximize throughput by supporting larger packet sizes:

OLT(config)#interface GE0/0/0
OLT(config-if)#mtu 9000
OLT(config-if)#exit
OLT(config)#write

Verify: show interface GE0/0/0 | include MTU should show 9000

Caution: Ensure upstream device also supports 9000 MTU; route all intermediate devices (switches) must support jumbo frames.

Option E: Check OLT Firmware Version for 10G Support

Verify your firmware supports 10G:

OLT#show version
System Information:
  Product Name: VSOL OLT-8004
  Firmware Version: v2.5.1
  Build Date: 2024-12-15
  Hardware Version: 1.2

10G Support Matrix (typical):

• OLT-8004, OLT-8008: v2.2+ supports 10G
• OLT-8016: v1.8+ supports 10G
• OLT-4416: Limited to 1G (no 10G uplink)

Upgrade firmware if 10G is not working: Check VSOL support portal for latest release notes.

Option F: Configure Link Aggregation (LAG) for Multiple 10G Uplinks

Bond multiple 10G ports for redundancy and load balancing:

OLT(config)#interface port-channel 1
OLT(config-if)#description "Uplink LAG 10G"
OLT(config-if)#exit
OLT(config)#interface GE0/0/0
OLT(config-if)#channel-group 1 mode active
OLT(config-if)#exit
OLT(config)#interface GE0/0/1
OLT(config-if)#channel-group 1 mode active
OLT(config-if)#exit
OLT(config)#write

Verify: show interface port-channel 1 should show aggregated bandwidth

Option G: Enable LLDP (Link Layer Discovery Protocol) on 10G Port

Auto-discover upstream device capabilities:

OLT(config)#lldp run
OLT(config)#interface GE0/0/0
OLT(config-if)#lldp send-mgmt-address
OLT(config-if)#exit
OLT(config)#write

Check discovered peers: show lldp neighbors

Option H: Set Port Speed to Forced 10G (No Auto-Negotiation)

Force 10G even if auto-negotiation fails:

OLT(config)#interface GE0/0/0
OLT(config-if)#speed 10000
OLT(config-if)#duplex full
OLT(config-if)#exit
OLT(config)#write

Verify: show interface GE0/0/0 should show 10Gbps, full duplex

Option I: Monitor Optical Signal Health Over Time

Log transceiver signal degradation:

OLT#show transceiver GE0/0/0 history
Sample  Time        RX Power  TX Power  Temperature
1       14:23:10    -1.2 dBm  +1.5 dBm  34°C
2       14:33:10    -1.5 dBm  +1.3 dBm  35°C
3       14:43:10    -1.8 dBm  +0.9 dBm  36°C
[Signal degrading—fiber may need cleaning]

If RX power drops >0.5 dBm over time, proactively clean fiber.

Option J: Schedule 10G Configuration During Maintenance Window

Apply 10G mode change and reload at off-peak time:

OLT(config)#scheduler event set giu mode 02:00
Configuration applied at 02:00 UTC
OLT(config)#scheduler reload 02:15
System will reload at 02:15 UTC
OLT(config)#write

Ensures minimal customer impact. Verify with show scheduler

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Related Guides

• VSOL OLT Firmware Upgrade via TFTP – Update firmware to enable advanced features
• GPON VLAN Configuration – Network segmentation on VSOL OLTs
• EPON VLAN Configuration – Alternative OLT type configuration
• Network VLAN Configuration – Fundamental VLAN concepts
• Jumbo Frames Configuration – Optimize throughput with larger packet sizes

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✅ 10G port enablement complete! Your VSOL OLT uplink is now operating at 10 Gigabit speeds. Monitor optical signal strength regularly (check RX/TX power monthly) to ensure link stability and longevity.