Cisco Catalyst 8500 and 8500L Series Edge Platforms Software Configuration Guide

Bay configuration C8500-12X4QC

Updated: February 6, 2026

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Overview

Bay configuration examples
Bay configuration C8500-12X
Bay configuration C8500-20X6C

Overview

Provides details and examples for configuring hardware bays on specific Catalyst 8500 models. Use these procedures to change interface modes and optimize traffic speeds across different built-in adapters.

On C8500-12X4QC there are three built-in EPAs that are configurable.

This table describes the port details:

Table 1. Bay configuration for C8500-12X4QC
Bay Number	EPA	Port Configuration	Interface numbers
Bay 0 8xSFP+	1/10G EPA	Eight 1/10G interfaces - TE0 - TE7 Disabled when 100G port in used in Bay 1	0/0/0 0/0/1 0/0/2 0/0/3 0/0/4 0/0/5 0/0/6 0/0/7 0/0/8
Bay 1 4xSFP+/1xQSFP	1/10/40/100G EPA	Four 1/10G interfaces active - TE0 - TE3 (interfaces 0/1/0 … 0/1/3) The bay can be used in these modes: Four 1/10G interfaces One 40G interface active One 100G interface. This utilizes the eight 1/10G ports of Bay 0	0/1/0 0/1/1 0/1/2 0/1/3
Bay 2 3xQSFP	40/100G EPA	Three 40G interfaces (0/1/0 to 0/1/2) One 100G interface (0/0/0) (0/0/0)	0/0/0 0/1/0 0/1/1 0/1/2

Note

The speed of a 10G interface can be 1G or 10G based on the SFP transceiver plugged into to the port. Even when the speed changes the interface name is still indicated as TenGigabitEthernet.

By default , C8500-12X4QC operates Bay 1 in 10G mode and Bay 2 in 40G mode. The Bay 1 mode can be changed from 10G to 40G to 100G and vice versa. But if Bay 1 is set to 100G, all ports of Bay 0 move to admin down state and the ports are no longer functional.

The Bay 2 mode can be changed from 40G to 100G and vice versa. The mode change on Bay 2 does not impact traffic on Bay 1.

Use the show platform and show ip interface commands to view the bay and interface details:

Router#show platform
Chassis type: C8500-12X4QC

Slot      Type                State                 Insert time (ago)
--------- ------------------- --------------------- -----------------
0         C8500-12X4QC        ok                    1w3d
 0/0      BUILTIN-8x1/10G     ok                    1w3d
 0/1      BUILTIN-100/40/4x10Gok                    00:04:53
 0/2      BUILTIN-100G/3X40G  ok                    00:08:16
R0        C8500-12X4QC        ok                    1w3d
 R0/0                         ok, active            1w3d
 R0/1                         ok, standby           1w3d
F0        C8500-12X4QC        ok, active            1w3d
P0        AIR-AC-750W-R       ok                    1w3d
P1        AIR-AC-750W-R       ps, fail              1w3d
P2        C8500-FAN-1R        ok                    1w3d

Slot      CPLD Version        Firmware Version
--------- ------------------- ---------------------------------------
0         19020715            12.2(20181120:104547) [user-gd_secur...
R0        19020715            12.2(20181120:104547) [user-gd_secur...
F0        19020715            12.2(20181120:104547) [user-gd_secur...

Router#show ip interface
Te0/0/0                unassigned      YES NVRAM  down                  down
Te0/0/1                unassigned      YES NVRAM  down                  down
Te0/0/2                unassigned      YES NVRAM  down                  down
Te0/0/3                unassigned      YES NVRAM  down                  down
Te0/0/4                unassigned      YES NVRAM  down                  down
Te0/0/5                unassigned      YES NVRAM  down                  down
Te0/0/6                unassigned      YES NVRAM  down                  down
Te0/0/7                unassigned      YES NVRAM  down                  down
Te0/1/0                unassigned      YES NVRAM  down                  down
Te0/1/1                unassigned      YES NVRAM  down                  down
Te0/1/2                unassigned      YES NVRAM  down                  down
Te0/1/3                unassigned      YES NVRAM  down                  down
Fo0/2/0                unassigned      YES unset  down                  down
Fo0/2/4                unassigned      YES unset  down                  down
Fo0/2/8                unassigned      YES unset  down                  down
GigabitEthernet0       10.104.33.213   YES NVRAM  up                    up
Router#

Bay configuration examples

These examples show how mode can be changed on C8500-12X4QC to achieve different traffic speeds:

This example shows how to change to 40G mode on Bay 1 of C8500-12X4QC:

Router(config)# hw-module subslot 0/1 mode 40G
Present configuration of this subslot will be erased and will not be restored.
CLI will not be available until mode change is complete and EPA returns to OK state.
Do you want to proceed? [confirm]

The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
*Oct 29 17:58:10.020 IST: BUILTIN-100/40/4x10G[0/1] : config for spa port 0 would be lost
*Oct 29 17:58:10.028 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 17:58:10.028 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 17:58:10.028 IST: BUILTIN-100/40/4x10G[0/1] : TenGigabitEthernet0/1/0 moved to default config
*Oct 29 17:58:10.028 IST: BUILTIN-100/40/4x10G[0/1] : config for spa port 1 would be lost
*Oct 29 17:58:10.035 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 17:58:10.036 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as 
:
:
*Oct 29 17:58:11.060 IST: BUILTIN-100/40/4x10G[0/1] : Old mode cleanup done!
*Oct 29 17:58:11.061 IST: %SPA_OIR-6-OFFLINECARD: SPA (BUILTIN-100/40/4x10G) offline in subslot 0/1
*Oct 29 17:58:16.297 IST: BUILTIN-100/40/4x10G[0/1] : Number of ports 1
*Oct 29 17:58:16.298 IST: BUILTIN-100/40/4x10G[0/1] : XCVR namestring create: Maximum number of XCVR = 1

This example shows how to change to 40G mode to 100G on Bay 1 of C8500-12X4QC:

Router(config)# hw-module subslot 0/1 mode 100G
Changing mode of subslot 0/1 to 100G will cause EPA in subslot 0/0 to go offline
Present configuration of this subslot will be erased and will not be restored.
CLI will not be available until mode change is complete and EPA returns to OK state.
Do you want to proceed? [confirm]

*Oct 29 18:09:01.360 IST: BUILTIN-100/40/4x10G[0/1] : config for spa port 0 would be lost
*Oct 29 18:09:01.368 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:09:01.368 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
The "[no] negotiation auto" command will have no effect with this interface
*Oct 29 18:09:01.368 IST: BUILTIN-100/40/4x10G[0/1] : FortyGigabitEthernet0/1/0 moved to default config
*Oct 29 18:09:02.368 IST: BUILTIN-8x1/10G[0/0] : config for spa port 0 would be lost
:
:
*Oct 29 18:09:03.446 IST: %SPA_OIR-6-OFFLINECARD: SPA (BUILTIN-100/40/4x10G) offline in subslot 0/1
*Oct 29 18:09:08.790 IST: BUILTIN-100/40/4x10G[0/1] : Number of ports 1
*Oct 29 18:09:08.792 IST: BUILTIN-100/40/4x10G[0/1] : XCVR namestring create: Maximum number of XCVR = 1
Router(config)#
*Oct 29 18:09:15.552 IST: %SPA_OIR-6-ONLINECARD: SPA (BUILTIN-100/40/4x10G) online in subslot 0/1

This example shows how to change to 10G mode from 100G on Bay 1 of C8500-12X4QC:

Router(config)# hw-module subslot 0/1 mode 10G
Present configuration of this subslot will be erased and will not be restored.
CLI will not be available until mode change is complete and EPA returns to OK state.
Do you want to proceed? [confirm]
*Oct 29 18:14:36.484 IST: %PLATFORM_SCC-1-AUTHENTICATION_FAIL: Chassis authentication failed

*Oct 29 18:14:38.219 IST: BUILTIN-100/40/4x10G[0/1] : config for spa port 0 would be lost
*Oct 29 18:14:38.227 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:14:38.227 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:14:38.227 IST: BUILTIN-100/40/4x10G[0/1] : HundredGigE0/1/0 moved to default config
*Oct 29 18:14:39.228 IST: BUILTIN-100/40/4x10G[0/1] : Received mode change request from 100G to 10G! system_configured TRUE
*Oct 29 18:14:39.230 IST: %IOSXE_OIR-6-SOFT_RELOADSPA: SPA(BUILTIN-100/40/4x10G) reloaded on subslot 0/1
*Oct 29 18:14:39.230 IST: BUILTIN-100/40/4x10G[0/1] : EPA moving from 100G mode to 10G mode
*Oct 29 18:14:39.230 IST: BUILTIN-100/40/4x10G[0/1] : config for spa port 0 would be lost
*Oct 29 18:14:39.231 IST: BUILTIN-100/40/4x10G[0/1] : Old mode cleanup done!
*Oct 29 18:14:39.232 IST: %SPA_OIR-6-OFFLINECARD: SPA (BUILTIN-100/40/4x10G) offline in subslot 0/1
*Oct 29 18:14:44.472 IST: BUILTIN-100/40/4x10G[0/1] : Number of ports 4
*Oct 29 18:14:44.475 IST: BUILTIN-100/40/4x10G[0/1] : XCVR namestring create: Maximum number of XCVR = 4
*Oct 29 18:15:03.336 IST: %SPA_OIR-6-ONLINECARD: SPA (BUILTIN-100/40/4x10G) online in subslot 0/1

This example shows how to change to 100G mode from 100G on Bay 2 of C8500-12X4QC:

Router(config)# hw-module subslot 0/2 mode 100G
Present configuration of this subslot will be erased and will not be restored.
CLI will not be available until mode change is complete and EPA returns to OK state.
Do you want to proceed? [confirm]

*Oct 29 18:17:03.394 IST: BUILTIN-100G/3X40G[0/2] : config for spa port 0 would be lost
*Oct 29 18:17:03.401 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:17:03.401 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:17:03.401 IST: BUILTIN-100G/3X40G[0/2] : FortyGigabitEthernet0/2/0 moved to default config
*Oct 29 18:17:03.401 IST: BUILTIN-100G/3X40G[0/2] : config for spa port 1 would be lost
*Oct 29 18:17:03.406 IST: BUILTIN-100G/3X40G[0/2] : Breakout XCVR type QSFP 4X10G AC7M (546) is not allowed as XCVR port Fortyrnet0/2/0 is not configured in breakout
*Oct 29 18:17:03.406 IST: %IOSXE_EPA-3-XCVR_PROHIBIT: Transceiver is prohibited to come online for interface FortyGigabitEther
*Oct 29 18:17:03.407 IST: BUILTIN-100G/3X40G[0/2] : XCVR prohibited on port FortyGigabitEthernet0/2/0, epa_name=BUILTIN-100G/3=FortyGigabitEthernet0/2/0, xcvr_speed=40000000, admin_state=UNSHUT xcvr_type=546

*Oct 29 18:17:03.409 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:17:03.409 IST: %SYS-5-CONFIG_P: Configured programmatically by process Exec from console as console
*Oct 29 18:17:03.409 IST: BUILTIN-100G/3X40G[0/2] : FortyGigabitEthernet0/2/4 moved to default config
*Oct 29 18:17:03.409 IST: BUILTIN-100G/3X40G[0/2] : config for spa port 2 would be lost
:
:
*Oct 29 18:17:09.686 IST: BUILTIN-100G/3X40G[0/2] : XCVR namestring create: Maximum number of XCVR = 1
Router(config)#
Router(config)#
*Oct 29 18:17:16.017 IST: %SPA_OIR-6-ONLINECARD: SPA (BUILTIN-100G/3X40G) online in subslot 0/2

Bay configuration C8500-12X

On C8500-12X4 there is one built-in EPA that supports ports TE0 - TE11 for SFP/SFP+ transceivers.

The speed of a 10G interface can be 1G or 10G based on the SFP transceiver plugged into to the port. Even when the speed changes the interface name is still indicated as TenGigabitEthernet.

Bay configuration C8500-20X6C

On C8500-20X6C there are two built-in EPAs that are configurable.

Table 1. Bay configuration for C8500-20X6C
Bay Number	EPA	Port Configuration	Interface numbers
Bay 0 20xSFP+	1/10G EPA	Twenty 1G interfaces Twenty 10G interfaces Twenty 1/10G interfaces	0/0/0, 0/0/1, 0/0/2, 0/0/3, 0/0/4, 0/0/5, 0/0/6, 0/0/7, 0/0/8,0/0/9, 0/0/10, 0/0/11, 0/0/12,0/0/13, 0/0/14, 0/0/15, 0/0/16,0/0/17, 0/0/18, 0/0/19
Bay 1 6xQSFP+	40/100G EPA	Six 40/100G interfaces active The bay can be used in these modes: Six 40G interfaces Six 100G interfaces Six 40/100G interfaces	0/1/0, 0/1/1, 0/1/2, 0/1/3, 0/1/4, 0/1/5

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