Overview

ZTE OLT (Optical Line Terminal) devices are widely deployed in FTTx networks globally, including the popular ZTE C300 and C600 series. This FAQ addresses real technical concerns from pre-sales sizing to post-sales CLI troubleshooting, helping network engineers and procurement teams make fast, informed decisions.

Frequently Asked Questions

Q1: What is the maximum GPON capacity of the ZTE C600 OLT?

The ZTE C600 OLT supports up to 16 service slots, each capable of housing a 16-port GPON line card, giving a theoretical maximum of 256 GPON ports per chassis. With each GPON port supporting up to 128 ONUs (optical network units) in typical deployments, the C600 can address over 32,000 ONUs per OLT, though real-world limits depend on the GPON chipset and service profile configurations.

Q2: Is the ZTE OLT C300 compatible with third-party ONUs, such as Huawei or Nokia?

In standard GPON mode, ZTE OLTs require ZTE-proprietary ONU authentication and OMCI management for full feature support. However, some third-party ONUs can work in “transparent” or “compatible” mode if they follow G.984 standards, but without guaranteed advanced features (DBA, software upgrade, VLAN stacking). For carrier-grade stability, ZTE recommends using ZTE-branded ONUs or formally validated third-party firmware from ZTE’s compatibility list.

Q3: What are the main differences between ZTE C300 and C600 OLTs for deployment planning?

The ZTE C600 is the high-density, next-generation platform with up to 800G switching capacity per chassis, while the C300 is a legacy series with lower density (typically 8 slots) and approximately 240G switching capacity. Key differences: C600 supports 100GE uplinks, 16-port GPON/XG-PON combo cards, and in-service software upgrades (ISSU); C300 is limited to 10GE uplinks and requires reboot for major version changes. Choose C600 for new FTTH/5G backhaul builds; C300 may suffice for compact or existing networks.

Q4: How do I perform basic CLI configuration for a new ZTE OLT (C600) — VLAN and GPON port setup?

Basic ZTE OLT CLI configuration involves three steps: (1) Create the service VLAN: vlan 100 smart then port vlan 100 1/1/1 tag; (2) Configure the GPON port: interface gpon-olt_1/2/1 then onu 1 type ZTEG type-class; (3) Bind VLAN to ONU: service-port 1 vlan 100 gpon-olt_1/2/1 onu 1 eth_1 inbound traffic-limit outbound traffic-limit. Always commit changes using write after verification.

Q5: Why are some ONTs continuously losing sync (flapping) on my ZTE OLT, and how to troubleshoot?

Persistent ONT flapping on a ZTE OLT is most often caused by optical power imbalance (RX too high or too low) or a defective splitter port. First, check the ONT’s optical parameters: show onu optics gpon-olt_1/1/1 onu 1 — ensure RX power is between -8dBm and -27dBm (ideal -18dBm). Second, verify the OLT PON port’s FEC errors: show interface gpon-olt_1/1/1 fec. Third, check for rogue ONUs by temporarily disconnecting individual ONTs from the splitter. High flapping often resolves after replacing the splitter or cleaning fiber connectors.

Q6: What is the maximum distance supported by ZTE OLT GPON ports in real deployment?

The ZTE OLT GPON standard maximum fiber distance is 20 km under Class B+ optics, with a logical reach of up to 60 km using ZTE’s extended reach features (when using Class C+ optics and adjusting the ranging parameters). In practice, most deployments stay within 20 km to maintain the standard 1:64 split ratio and full upstream bandwidth. For distances beyond 20 km, you must reduce the split ratio (e.g., 1:16) and use higher-category SFP modules like Class C++.

Q7: How do I upgrade the firmware on a ZTE OLT C300 without service interruption?

The ZTE C300 does not support ISSU (In-Service Software Upgrade). To upgrade without a full outage, use the master-backup control switchover method: (1) Upload the new firmware to the standby control card: copy tftp://192.168.1.100/ZTE_C300_6.0.bin slot-2; (2) Manually switch control to the standby card: redundancy switchover force; (3) Upgrade the now-standby card. This causes a brief (<3s) PON traffic hit. For zero-downtime oner requirements, use C600 with ISSU support instead.

Q8: What management protocols does ZTE OLT support for integration with existing NMS or SDN controllers?

ZTE OLTs support SNMP v1/v2c/v3 (full standard MIBs: ZTE-PON-MIB, IF-MIB), NETCONF over SSH, and RESTCONF for modern orchestration. The C600 series additionally supports OpenConfig YANG models for telemetry streaming. For legacy integration, use CLI over SSH or Telnet. For ZTE’s proprietary NMS, the UniCenter platform provides full northbound interfaces.