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1/17
2012
Carole Warner Reece

Migrating to Nexus 7000 from Catalyst 6500 and 4500 Switches as of NX-OS 6.0

I decided to refresh my earlier article on Migrating to Nexus 7000 from Catalyst 6500 and 4500 Switches with some 5.x/6.0 updates. The current set of NX-OS 5.x/6.0 CLI commands in are pretty similar to the 12.2 IOS CLI on Catalyst 4500 and 6500s. I’ve also added some additional commands that I felt may be useful, such as the BGP commands.

With NX-OS, you can also use the “?” to get help and prompts, commands can be abbreviated, and the [Tab] key will auto-fill in unambiguous commands.

Some caveats: NX-OS does not support all the features of IOS, for example, acting as a DHCP server and NTP authentication.

IOS Commands (Nexus NX-OS Commands when different)

Function

show version Displays information about the currently running system software image and an overview of the installed hardware.
show module Displays information about the installed modules including module number, module type, number of ports on each module, module MAC addresses, and the module status.
router(config)#do show command


router(config)#show command
! or
router(config)#do show command 
View existing configuration information from the configuration command prompt using show commands.

Note:
For NX-OS, the [Tab] key and “?” will work for Exec mode commands inside of configuration mode. The use of “do” in NX-OS is currently working, but is not documented.
router(config)# do Exec-command
router(config)# Exec-command
! or
router(config)#do Exec-command
View existing configuration information from the configuration command prompt.

Note:
For NX-OS, the [Tab] key and “?” will work for Exec mode commands inside of configuration mode. The use of “do” in NX-OS is currently working, but is not documented.
reload Reloads the operating system for the entire device
Note:
For the Nexus 7000, this command works only in the default VDC.

! 6500
hw-module module slot reset
! 4500
no hw-module [slot | module] number power
hw-module [slot | module] number power
 

reload module mod-#

Reloads a module in the device by turning power off then on.

Note: For the Nexus 7000, this command works only in the default VDC

service timestamps [debug | log] [uptime | datetime [msec]] [localtime] [show-timezone] [year]

debug logging
logging timestamp {microseconds | milliseconds | seconds}
Apply a time stamp to debugging messages or system logging messages.

Note: In NX-OS, to enable debug logging configure ‘debug logging’ command. NX-OS does not have as many options for timestamps.

service password-encryption
! No equivalent NX-OS command
Note: By default, NX-OS encrypts plain text passwords and enables password strength checking.

logging buffered [discriminator discr-name] [buffer-size] [severity-level]


logging logfile logfile-name severity-level [size bytes]

Enable system message logging to a local buffer
username name {nopassword | password password | password encryption-type encrypted-password}
username user-id [password [0 | 5]  password] 
Create and configure a user account.

Note:
By default, NX-OS encrypts plain text passwords and enables password strength checking.
aaa new-model
aaa authentication login default group tacacs+ local
aaa authentication login console none
aaa authentication enable default none
aaa authentication ppp default local
aaa accounting exec default start-stop group tacacs+
aaa accounting commands 0 -15 start-stop group tacacs+
aaa accounting commands 15 default start-stop group tacacs+
aaa authorization commands level
aaa authorization config-commands
aaa session-id common
aaa authentication login default {group tacacs+ | local}
aaa authentication login console none
aaa user default-role
aaa accounting default group tacacs+
aaa authorization commands default
aaa authorization config-commands default

Configuring AAA.  

Note: Not all commands are supported on the NX-OS.

clock timezone zone hours-offset [minutes-offset]
clock summer-time zone recurring [week day month hh:mm week day month hh:mm [offset]]

clock timezone zone-name offset-hours offset-minutes
clock summer-time zone-name start-week start-day start-month start-time end-week end-day end-month end-time offset-minutes

Configure the time zone offset from Coordinated Universal Time (UTC) as well as daylight savings time.

ip classless
 

! No equivalent NX-OS command

This commands is not available in NX-OS.
ip subnet-zero
no ip source-route
no ip bootp server

! No equivalent NX-OS command
These commands are not available in NX-OS.

no ip domain-lookup
ip domain-nam
e [vrf vrf-name] name
ip name-server [vrf vrf-name] ip-address
no ip domain-lookup
ip domain-name
domain-name [use-vrf name]
 
ip name-server
ip-address [use-vrf name]

Disable DNS lookup feature and configure a domain name and name server.
ip ssh time-out seconds
ip ssh authentication-retries tries
ip ssh version 2ip
feature ssh
ssh key {dsa [force] | rsa [length [force]]}
Enable an SSH server.

Note:
The Cisco NX-OS commands for SSH are different from the Cisco IOS commands. NX-OS software supports only SSHv2.
power redundancy-mode {redundant | combined}
power redundancy-mode {combined | insrc-redundant | ps-redundant | redundant}
Configure the power supply redundancy mode

! 6500
no power enable module mod-#
! 4500
no hw-module [slot | module] number power
 poweroff module mod-#

Powers off a module from configuration mode. 
redundancy
mode sso
main-cpu
auto-sync standard
! No equivalent NX-OS command
Configure CPU redundancy.

Note:
: The Nexus 7000 supports dual supervisor modules to provide 1+1 redundancy for the control and management plane. Only one of the supervisor modules is active at any given time, while the other acts as a standby backup. No configuration commands are needed.
spanning-tree mode [pvst | mst | rapid-pvst]
spanning-tree mode [rapid-pvst | mst]
Default mode for IOS is PVST; default mode for NX-OS is RPVST.

Note:
When you enter the command, all STP instances are stopped for the previous mode and are restarted in the new mode.
spanning-tree extend system-id
! No equivalent NX-OS command
Enable the extended system ID feature on a chassis that supports 1024 MAC addresses.
Note:
NX-OS does not use this command, the extended system ID is always automatically enabled in NX-OS devices.
spanning-tree vlan vlan-id  priority value Set the STP bridge priority
vlan internal allocation policy ascending
! No equivalent NX-OS command
Configure the internal VLAN allocation scheme.

Note:
NX-OS does not support this command.

interface type slot/number
switchport
switchport mode access
switchport access vlan vlan-id
spanning-tree portfast
[speed {10 | 100 | 1000 | auto [10 | 100 | 1000] | nonegotiate}]
interface
type slot/number
switchport
switchport host
switchport access vlan
 vlan-id
[speed {10 | 100 | 1000
|
auto [10 |
100 | 1000] | 10000 | auto}]
vlan 
 vlan-id

Configure a Layer 2 access port.

Note:
NX-OS uses “Ethernet” as the type for all FastEthernet / GigabitEthernet / Ten Gigabit Ethernet interfaces.
The VLAN in the vlan-id needs to be created so that the interface will come up.
interface type slot/number
switchport
switchport mode trunk
[switchport trunk allowed vlan vlan-id]
switchport trunk encapsulation [isl | dot1 | negotiate]
[switchport trunk allowed vlan add vlan-id]
[speed {10 | 100 | 1000 | auto [10 | 100 | 1000] | nonegotiate}]
interface 
 type slot/number
switchport
switchport mode trunk
[switchport trunk allowed vlan
vlan-id]
[switchport trunk allowed vlan add
vlan-id]
[speed {10 | 100 | 1000
| auto [10 | 100 | 1000] | 10000 | auto}]
Configure a Layer 2 trunk port.

Note:
NX-OS only supports 802.1Q encapsulation.
vlan vlan-#
interface vlan-#
no shutdown
vlan vlan-#
feature interface-vlan
interface vlan-#
no shutdown
Configure a VLAN interface

Note:
In NX-OS, the interface-vlan feature needs to be enabled before an interface VLAN can be configured. The VLAN needs to be defined as well for the interface to come up

interface port-channel channel-#
switchport

switchport mode . . .
interface type slot/number
switchport
channel-group group_number mode {active | auto | desirable | on | passive}
feature LACP
interface port-channel
channel-#
switchport
switchport mode . . .
interface
 type slot/number
switchport
channel-group
channel-
 number   [force]  [mode{on | active | passive}] 

Configure a Layer 2 LACP port channel.
Note:
In NX-OS, the LACP feature needs to be enabled before it can be used.
vtp domain domain-name Configure the VTP domain name

vtp {server | client | transparent | off}
 

feature vtp
vtp {server | client | transparent | off}

Configure the VTP mode.

Note:
By default, VTP mode is off for NX-OS.
udld {enable | aggressive}
feature udld
Enable UDLD globally on a device.
ip route prefix mask next-hop-address
  
ip route ip-prefix/length next-hop-address
Configure static routes.
ip access-list extended access-list-name
[sequence-number] {permit | deny} protocol source source-wildcard destination destination-wildcard . . .

ip access-list access-list-name
[sequence-number] {permit | deny} protocol source destination . . .
 
Create or configure an IPv4 ACL

Note:
NX-OS supports one type of IPv4 ACL which is similar to the named extended ACL in IOS.

ip access-list resequence access-list-name starting-sequence-number increment

  resequence access-list-type access-list access-list-name starting-sequence-number increment

Resequence an ACL.
router eigrp as-number
feature EIGRP
router eigrp
 instance-tag
[autonomous-system as-number]
Configure EIGRP routing.

Note:
In NX-OS, the EIGRP feature needs to be enabled before it can be used. You can use any case-sensitive alphanumeric string up to 20 characters as an instance tag. If you configure an instance-tag that does not qualify as an AS number, you must use the autonomous-system command to configure the AS number explicitly or this EIGRP instance will remain in the shutdown state
router(config-router)#
network ip-address [wildcard-mask]
interface type slot/number
ip address ip-prefix/length
ip router eigrp instance-tag
 

Configure a network in EIGRP.

Note:
For NX-OS, a network is configured in EIGRP by associating it through an interface the router uses to connect to the area. NX-OS uses CIDR notation for IP addresses, but can accept the ip-address mask format as well.

router ospf process-id
feature OSPF
router ospf
 instance-tag
Configure OSPF routing.

Note:
In NX-OS, the OSPF feature needs to be enabled before it can be used. The instance-tag is locally assigned and can be any alphanumeric string or positive integer.
router(config-router)#
network ip-address wildcard-mask area area-id
interface type slot/number
ip address ip-prefix/length
ip router ospf instance-tag area area-id 
 
Configure a network in OSPF.

Note:
For NX-OS, a network is configured in OSPF by associating it through an interface the router uses to connect to the area.

router ospf process-id
auto-cost reference-bandwidth mbps

 

router ospf instance-tag
auto-cost reference-bandwidth
bandwidth [Gbps | Mbps]

Configure a reference bandwidth for OSPF.

Note: For IOS, the default is 100 Mb/s. For NX-OS, the default is 40Gb/s.

router bgp as-number
no synchronization
bgp router-id ip-address
bgp always-compare-med
bgp log-neighbor-changes
bgp deterministic-med
bgp bestpath med missing-as-worst
no auto-summary

 

feature bgp
router bgp
as-num
router-id
ip-address
bestpath med missing-as-worst

bestpath always-compare-med
log-neighbor-changes

Configure BGP routing.

Note: For NX-OS, the no synchronization and no auto-summary commands are enabled by default.

router bgp as-number
neighbor ip-address remote-as as-number
 network network-number [mask network-mask]

router bgp as-num
address-family ipv4 unicast
network
ip-prefix/length
neighbor
ip-address remote-as as-number

address-family ipv4 unicast
 

Advertise an IPv4 network in BGP.

router bgp as-number
neighbor peer-name peer-group
neighbor peer-name remote-as as-number
neighbor peer-name password 7 password
neighbor peer-name update-source Loopback0
neighbor peer-name send-community
neighbor peer-name timers 2 6
neighbor peer-name soft-reconfiguration inbound
neighbor ip-address-1 peer-group peer-name
neighbor ip-address-1 description descriptive-info
neighbor ip-address-2 peer-group peer-name
neighbor ip-address-2 description descriptive-info

router bgp as-number
template peer peer-name
remote-as
as-number
password 7
password
update-source
loopback0
timers 3 9
address-family ipv4 unicast
send-community
soft-reconfiguration inbound
neighbor
ip-address-1 remote-as as-number
inherit peer peer-name
description descriptive-info
neighbor ip-address-2 remote-as as-number
inherit peer peer-name
description descriptive-info

Configure BGP Peer Group/Template.
interface type slot/number
ip address ip-address mask
ip helper-address ip-address
standby [group-number] ip ip-address standby [group-number] timers hellotime holdtime
standby [group-number] priority priority
standby [group-number] prempt
f
eature hsrp
ip dhcp relay
interface
 type slot/number
ip address ip-prefix/length 
ip dhcp relay address
ip-address
hsrp
group-number
ip
ip-address
timers  
hellotime holdtime
 
priority  priority
prempt
Configure HSRP with an IP helper address to a DHCP server. Different command syntax is used. NX-OS also uses ‘hsrp’ as keyword, while IOS uses ‘standby’.

Note:
In NX-OS, the HSRP feature needs to be enabled before it can be used. To use the DHCP relay, DHCP services also has to be enabled. The HSRP holdtime needs to be at least 3x the hello time. NX-OS uses CIDR notation for IP addresses, but can accept the ip-address mask format as well.
Prior to NX-OS 4.2(1), the service dhcp command enabled the DHCP Relay feature. In NX-OS 4.2(1) the command was changed to ip dhcp relay.
ip dhcp pool name
! No equivalent NX-OS command
Configure a Dynamic Host Configuration Protocol (DHCP) address pool on a DHCP server.

Note:
The NX-OS supports DHCP snooping, and DHCP relay, but does not support acting as a DHCP server.
ip multicast-routing
feature PIM
Enable IP multicast routing
 ip prefix-list name seq seq-num permit prefix/length
  
Configure an IP prefix-list
ipv6 unicast-routing
interface type slot/number
ipv6 address  ipv6-prefix/prefix-length eui-64
interface  type slot/number
ipv6 address  ipv6-prefix/prefix-length eui-64
Enable IPv6 traffic forwarding on an interface.

Note:
NX-OS does NOT need to enable IPv6 routing globally.

ip telnet source-interface Loopback0
ip tftp source-interface Loopback0
ip domain-lookup source-interface Loopback0
ip flow-export source Loopback0
ip tacacs source-interface Loopback0
logging source-interface Loopback0
snmp-server trap-source Loopback0
ntp source Loopback0

 

aaa group server tacacs+ default use-vrf management
source-interface mgmt0
snmp-server source-interface trap mgmt0
snmp-server source-interface inform mgmt0
snmp-server host
ip-address use-vrf management
snmp-server host
ip-address source-interface mgmt0
ntp server ip-address use-vrf management
vrf context management
ip route
0.0.0.0/0 ip-address
interface mgmt0
ip address
ip-prefix/length
logging server ip-address serverity use-vrf management

Configure a management interface.

Note: The NX-OS management interface is in a separate management VRF.

ntp server ip-address   

Configure an NTP server as a time source.

Note: NX-OS previously needed the NTP enable command – this command was deprecated in 5.2(1). Starting with 5.2(1), NX-OS devices can serve as an NTP server for other devices in the network. (Use the ntp master [stratum] command to set the device as an authoritative NTP server.)

ntp authenticate
ntp authentication-key
number md5
value
ntp trusted-key
key-number
ntp update-calendar
ntp server ip-address key key-id 

 

! No NX-OS support for ntp update-calendar command

Configure NTP authentication options.

Note:
NX-OS does not currently support the ntp update-calendar command.

monitor session session-#
source interface type slot/number
monitor session session-# destination interface type slot/number
interface type slot/number
switchport
switchport monitor [ingress | learning]
monitor session session-number
description description

source interface
type slot/number
destination interface
type slot/number 
Enable SPAN sessions on interfaces or VLANs
snmp-server community RW-string RW acl-#
snmp-server community RO-string RO acl-#
snmp-server enable traps snmp authentication linkdown linkup coldstart warmstart
 snmp-server enable traps tty
snmp-server enable traps entity
snmp-server enable traps port-security
snmp-server enable traps config
snmp-server host ip-address string
snmp ifmib ifindex persist

snmp-server community RW-string RW
snmp-server community
 RO-string RO
snmp-server community
 RW-string use-acl acl-name
snmp-server community RO-string use-acl acl-name
snmp-server enable traps snmp authentication
snmp-server enable traps link 
snmp-server enable traps entity
snmp-server host ip-address string
 
Enable common SNMP options.

Note:
NX-OS syntax differs.
tacacs-server host ip-address
tacacs-server directed-request
tacacs-server key [0 | 7] key
feature tacacs+
tacacs-server host ip-address
tacacs-server directed-request
tacacs-server key [0 | 6 | 7] key
Configure TACACS+ server

I hope this gives you a useful overview of some common configuration and verification commands you may need when migrating.

Three useful Cisco documentation links for further information:

 http://www.cisco.com/en/US/products/ps9402/prod_command_reference_list.html – NX-OS command references

http://www.cisco.com/en/US/products/ps9402/products_installation_and_configuration_guides_list.html

http://docwiki.cisco.com/wiki/Cisco_Nexus_7000_NX-OS/IOS_Comparison_Tech_Notes — includes multiple articles comparing Cisco NX-OS and Cisco IOS features.

— cwr

Carole Warner Reece

Architect

A senior network consultant with more than fifteen years of industry experience, Carole is one of our most highly experienced network professionals. Her current focus is on the data center and on network infrastructure.

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Nick Kelly

Cybersecurity Engineer, Cisco

Nick has over 20 years of experience in Security Operations and Security Sales. He is an avid student of cybersecurity and regularly engages with the Infosec community at events like BSides, RVASec, Derbycon and more. The son of an FBI forensics director, Nick holds a B.S. in Criminal Justice and is one of Cisco’s Fire Jumper Elite members. When he’s not working, he writes cyberpunk and punches aliens on his Playstation.

 

Virgilio “BONG” dela Cruz Jr.

CCDP, CCNA V, CCNP, Cisco IPS Express Security for AM/EE
Field Solutions Architect, Tech Data

Virgilio “Bong” has sixteen years of professional experience in IT industry from academe, technical and customer support, pre-sales, post sales, project management, training and enablement. He has worked in Cisco Technical Assistance Center (TAC) as a member of the WAN and LAN Switching team. Bong now works for Tech Data as the Field Solutions Architect with a focus on Cisco Security and holds a few Cisco certifications including Fire Jumper Elite.

 

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He is an expert in working with groups to identify business needs, and align technology strategies to enable business strategies, building in agility and scalability to allow for future changes. John is experienced in the architecture and design of highly available, secure, network infrastructure and data centers, and has worked on projects worldwide. He has worked in both the business and regulatory environments for the design and deployment of complex IT infrastructures.