Configuration Guide for Cisco NCS 1004, IOS XR Release 25.x.x

Remote node management using GCC

Updated: July 31, 2026

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This concept explains remote node management using the General Communication Channel (GCC), highlighting how GCC enables centralized control and monitoring of network elements across distributed topologies.

Remote node management using GCC is a network management method that

leverages the General Communication Channel (GCC) embedded in optical transport networks,
delivers reliable, out-of-band communication between centralized controllers and remote network nodes, and
enables real-time monitoring, configuration, and maintenance activities without requiring direct physical access to each node.

Table 1. Feature History
Feature Name	Release Information	Feature Description
GCC Support for OTN-XP Card	Cisco IOS XR Release 7.3.2	The node supports a maximum of 48 GCC (GCC0 and GCC1) channels for each OTN-XP card.

From R7.2.1 onwards, the OTN-XP card provides OTU interface that supports communication channels between adjacent network elements or nodes using GCC bytes in the OTN header. Remote node management is supported over the GCC interface.

Figure 1. Remote Node Management in Linear Topology

The remote nodes can be dynamically discovered over the GCC interface using OSPF. The connectivity to the management network can be achieved using OSPF and static routes.

Note

The GCC2 and GCC0 interfaces are supported in NCS 1004. The GCC0 interface is supported on the Coherent DSP controller whereas the GCC2 interface is supported on the ODU controller.

Note

The GCC0 and GCC2 interfaces are supported in Muxponder and Muxponder slice modes. Only the GCC0 interface is supported in the Regeneration (Regen) mode.

From R7.2.1 onwards, the node supports GCC0 on the corresponding OTU2, OTU2e, and OTU4 interfaces. The node (Cisco FPGA) supports a maximum of 22 GCC channels for each card.

Note

The GCC0 and GCC1 interfaces are supported on OTN-XP card and GCC2 interface is not supported.

From R7.3.1 onwards, the node supports GCC0 on the corresponding OTU2, OTU2e, OTU4, and Coherent DSP interfaces, and GCC1 on OTN ODU controller (ODU2, ODU2E, ODU4, and ODUCn).

From R7.3.2 onwards, the node (Cisco FPGA) supports a maximum of 48 GCC (GCC0 and GCC1) channels for each card.

Supported and unsupported features of the GCC interface

This table lists supported and unsupported features for remote node management using the GCC interface.

Table 2. Feature Support Overview:
Feature/Functionality	Supported on GCC Interface?	Notes
gRPC protocol	No	gRPC is not supported over the GCC interface.
Open Config	No	Not supported due to lack of gRPC support.
Streaming telemetry	No	Not supported due to lack of gRPC support.
Tx and Rx packet count statistics	Yes	Only Tx and Rx packet count information is available in GCC
Remote node management (after initial provisioning)	Yes	Devices can be managed over GCC only when connected through the management network using GCC.
Initial provisioning and bring-up via GCC	No	Must use console or management Ethernet interface for initial setup.
Remote management after headless/HA event	May be impacted	Events like reloads or driver restarts at intermediate nodes may affect management of subsequent nodes.
IP fragmentation for SCP protocol	No	Not supported; reduce packet size to less than 1454 bytes as a workaround.
TCP MSS configuration to avoid fragmentation	Yes	Use `tcp mss <maximum segment size>` in global config mode.
Coherent DSP controller (QXP card) GCC0 interface	Yes	Supported on QXP card.
GCC0 speed on QXP card	Yes	7.7 Mbps.

Note

For operations not supported on the GCC interface, use the console or management Ethernet interface as alternatives. For SCP protocol, configure TCP MSS or IPv4 MTU settings to avoid IP fragmentation issues.

Supported protocols

These protocols are supported over the GCC interface:

PING
SSH
TELNET
SCP
TFTP
FTP
SFTP
HTTP
HTTPS
OSPF

Enable the GCC interface

Use this task to enable GCC0, GCC1, or GCC2 interfaces on various line cards (1.2T, OTN-XP) to support management and communication channels.

Procedure

Enter configuration mode.

Configure the controller and the GCC interface for a line card.


If you want to configure	Then use the command
GCC2 interface on the 1.2T card	controller odu4 R/S/I/P/L gcc2
GCC0 interface on the 1.2T card	controller CoherentDSP R/S/I/P/L gcc2
GCC0 interface for the OTN-XP card	controller {otu2 \| otu2e \| otu4} R/S/I/P/L gcc0
GCC1 interface for the OTN-XP card	controller {odu2 \| odu2e \| odu4 \| oducn} R/S/I/P/L gcc1

Example:

This sample configuration enables the GCC2 interface for the 1.2T line card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller odu4 0/1/0/0/1
RP/0/RP0/CPU0:ios(config-otu)#gcc2
RP/0/RP0/CPU0:ios(config-otu)#commit
RP/0/RP0/CPU0:ios(config-otu)#exit

This sample configuration enables the GCC0 interface for the 1.2T line card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller CoherentDSP0/0/1/1
RP/0/RP0/CPU0:ios(config-otu)#gcc0
RP/0/RP0/CPU0:ios(config-otu)#commit
RP/0/RP0/CPU0:ios(config-otu)#exit

This sample configuration enables the GCC0 interface for the OTN-XP line card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller otu2 0/0/0/4/1
RP/0/RP0/CPU0:ios(config-otu)#gcc0
RP/0/RP0/CPU0:ios(config-otu)#commit
RP/0/RP0/CPU0:ios(config-otu)#exit

This sample configuration enables the GCC1 interface for the OTN-XP line card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#controller odu2 0/0/0/4/1
RP/0/RP0/CPU0:ios(config-otu)#gcc1
RP/0/RP0/CPU0:ios(config-otu)#commit
RP/0/RP0/CPU0:ios(config-otu)#exit

Configure the GCC interface

Use this task to configure the GCC0, GCC1, and GCC2 interfaces on 1.2T and OTN-XP cards using static or loopback IP addresses.

Procedure

Enter configuration mode.

Specify the GCC2 interface for a line card.


If you want to configure	Then use the command
GCC2 interface on the 1.2T card	interface gcc2 R/S/I/P/L
GCC0 interface on the 1.2T card	interface gcc0 R/S/I/P
GCC0 interface on the OTN-XP card	interface gcc0 R/S/I/P
GCC1 interface on the OTN-XP card	interface gcc1 R/S/I/P

Use the command ipv4 address ipv4-address net-mask to set the IPv4 address for the interface.

Example:

This sample configures the GCC2 interface using the static IP address on the 1.2T line card

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#interface gcc2 0/1/0/0/1
RP/0/RP0/CPU0:ios(config-if)#ipv4 address 198.51.100.244 255.255.255.0
RP/0/RP0/CPU0:ios(config-if)#commit
RP/0/RP0/CPU0:ios(config-if)#exit
RP/0/RP0/CPU0:ios(config)#exit
RP/0/RP0/CPU0:ios#show run interface gcc2 0/1/0/0/1
interface GCC20/1/0/0/1
ipv4 address 10.1.1.1 255.255.255.0
!

This sample configures the GCC2 interface using the loopback IP address on 1.2T card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:R2(config)#interface gcc2 0/1/0/0/1
RP/0/RP0/CPU0:R2(config-if)#ipv4 unnumbered loopback 0
RP/0/RP0/CPU0:ios(config-if)#exit

This sample checks the status of GCC2 interface.

RP/0/RP0/CPU0:ios#show ipv4 interface brief
Wed Sep 22 17:10:04.190 IST
Interface IP-Address Status Protocol Vrf-Name
GCC20/0/0/0/1 198.51.100.234 Up Up default
GCC20/3/0/1/3 198.51.100.244 Up Up default
Loopback0 198.51.100.224 Up

This sample configures the GCC0 interface using the static IP address on 1.2T or OTN-XP card.enables the GCC1 interface for the OTN-XP line card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:ios(config)#interface gcc0 0/1/0/0
P/0/RP0/CPU0:ios(config-if)#ipv4 address 198.51.100.244 255.255.255.0
RP/0/RP0/CPU0:ios(config-if)#commit
RP/0/RP0/CPU0:ios(config-if)#exit
RP/0/RP0/CPU0:ios(config)#exit
RP/0/RP0/CPU0:ios#show run interface gcc0 0/1/0/0
interface GCC00/1/0/0
ipv4 address 198.51.100.244 255.255.255.0
!

This sample configures the the GCC0 interface using the loopback IP address on 1.2T or OTN-XP card.

RP/0/RP0/CPU0:ios#configure
RP/0/RP0/CPU0:R2(config)#interface gcc0 0/1/0/0
RP/0/RP0/CPU0:R2(config-if)#ipv4 unnumbered loopback 0
RP/0/RP0/CPU0:ios(config-if)#exit
RP/0/RP0/CPU0:ios(config)#exit

Note
The following configuration is required from R25.4.1 after configuring the GCC interface.
linux networking
vrf default
address-family ipv4
default-route software-forwarding
source-hint management-route interface MgmtEth0/RP0/CPU0/0
source-hint default-route interface MgmtEth0/RP0/CPU0/0

Configure static routes over the GCC interface

Use this task to configure the router to forward packets for specific networks or hosts via the GCC interface using manually defined routes.

Procedure

	1.	Enter configuration mode.
	2.	Enter the router static configuration mode.
	3.	Use the command address-family ipv4 unicast ip4 address default-gateway to enter address family configuration mode. This step also configures a routing session using standard IPv4 address prefixes. Example: `RP/0/RP0/CPU0:ios#configure RP/0/RP0/CPU0:ios(config)#router static address-family ipv4 unicast 0.0.0.0/0 10.105.57.1 RP/0/RP0/CPU0:ios(config)#exit`

Configure OSPF routes over the GCC interface

Enable OSPF dynamic routing between gateway and remote nodes using GCC interfaces.

This task enables OSPF over GCC interfaces, which facilitates efficient OSPF communication in specialized network environments.

Procedure

SUMMARY STEPS

Enter configuration mode and enable the OSPF routing process using the command router ospf process-id router-id ip-address
Assign the OSPF area and specify the interfaces to include using the command area area-id interface type R/S/I/P/L
On the remote node, redistribute connected routes into OSPF, using the command redistribute connected.
Exit the configuration mode upon completion.

DETAILED STEPS

	1.	Enter configuration mode and enable the OSPF routing process using the command router ospf process-id router-id ip-address Example:
	2.	Assign the OSPF area and specify the interfaces to include using the command area area-id interface type R/S/I/P/L
	3.	On the remote node, redistribute connected routes into OSPF, using the command redistribute connected.
	4.	Exit the configuration mode upon completion. Example: Gateway Node: `configure router ospf 1 router-id 192.0.2.89 area 0 interface Loopback0 ! interface MgmtEth0/RP0/CPU0/1 ! interface GCC20/0/0/0/1 ! interface GCC20/0/0/0/2` Remote Node: `configure router ospf 1 router-id 192.0.2.92 redistribute connected area 0 interface Loopback0 ! interface GCC20/0/0/0/1 ! interface GCC20/0/0/0/2`

OSPF is configured over GCC interfaces, enabling gateway and remote nodes to dynamically exchange routing information.

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