Cisco MDS 9000 Family CLI Configuration Guide
Configuring IPv4 for Gigabit Ethernet Interfaces
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Table of Contents

Configuring IPv4 for Gigabit Ethernet Interfaces

About IPv4

Basic Gigabit Ethernet Configuration for IPv4

Configuring Interface Descriptions

Configuring Beacon Mode

Configuring Autonegotiation

Configuring the MTU Frame Size

Configuring Promiscuous Mode

Verifying Gigabit Ethernet Connectivity

VLANs

About VLANs for Gigabit Ethernet

Configuring the VLAN Subinterface

Interface Subnet Requirements

Configuring Static IPv4 Routing

Displaying the IPv4 Route Table

IPv4-ACLs

Gigabit Ethernet IPv4-ACL Guidelines

Applying IPv4-ACLs on Gigabit Ethernet Interfaces

ARP Cache

Displaying ARP Cache

Clearing ARP Cache

Displaying IPv4 Statistics

Default Settings

Configuring IPv4 for Gigabit Ethernet Interfaces

Cisco MDS 9000 Family supports IP version 4 (IPv4) on Gigabit Ethernet interfaces. This chapter describes how to configure IPv4 addresses and other IPv4 features.

This chapter includes the following topics:

About IPv4

Both FCIP and iSCSI rely on TCP/IP for network connectivity. On each IPS module or MPS-14/2 module, connectivity is provided in the form of Gigabit Ethernet interfaces that are appropriately configured. This section covers the steps required to configure IP for subsequent use by FCIP and iSCSI.


Note For information about configuring FCIP, see Chapter41, “Configuring FCIP” For information about configuring iSCSI, see Chapter43, “Configuring iSCSI”


A new port mode, called IPS, is defined for Gigabit Ethernet ports on each IPS module or MPS-14/2 module. IP storage ports are implicitly set to IPS mode, so it can only be used to perform iSCSI and FCIP storage functions. IP storage ports do not bridge Ethernet frames or route other IP packets.

Each IPS port represents a single virtual Fibre Channel host in the Fibre Channel SAN. All the iSCSI hosts connected to this IPS port are merged and multiplexed through the single Fibre Channel host.

In large scale iSCSI deployments where the Fibre Channel storage subsystems do not require explicit LUN access control for every host device, use of proxy-initiator mode simplifies the configuration.


Note The Gigabit Ethernet interfaces on the MPS-14/2 module do not support EtherChannel.



Note To configure IPv6 on a Gigabit Ethernet interface, see the “Configuring IPv6 Addressing and Enabling IPv6 Routing” section.



Tip Gigabit Ethernet ports on any IPS module or MPS-14/2 module should not be configured in the same Ethernet broadcast domain as the management Ethernet port. They should be configured in a different broadcast domain, either by using separate standalone hubs or switches or by using separate VLANs.


Basic Gigabit Ethernet Configuration for IPv4

Figure 46-1 shows an example of a basic Gigabit Ethernet IP version 4 (IPv4) configuration.

Figure 46-1 Gigabit Ethernet IPv4 Configuration Example

 

 


Note The port on the Ethernet switch to which the MDS Gigabit Ethernet interface is connected should be configured as a host port (also known as access port) instead of a switch port. Spanning tree configuration for that port (on the Ethernet switch) should be disabled. This helps avoid the delay in the management port coming up due to delay from Ethernet spanning tree processing that the Ethernet switch would run if enabled. For Cisco Ethernet switches, use either the switchport host command in Cisco IOS is or the set port host in Catalyst OS. Refer to the configuration guide for your Ethernet switch.


To configure the Gigabit Ethernet interface for the example in Figure 46-1, follow these steps:

Command
Purpose

Step 1

switch# config terminal

switch(config)#

Enters configuration mode.

Step 2

switch(config)# interface gigabitethernet 2/2

switch(config-if)#

Enters the interface configuration mode on the Gigabit Ethernet interface (slot 2, port 2).

Step 3

switch(config-if)# ip address 10.1.1.100 255.255.255.0

Enters the IPv4 address (10.1.1.100) and subnet mask (255.255.255.0) for the Gigabit Ethernet interface.

Step 4

switch(config-if)# no shutdown

Enables the interface.

This section includes the following topics:

Configuring Interface Descriptions

See the “About Interface Descriptions” section for details on configuring the switch port description for any interface.

Configuring Beacon Mode

See the “About Beacon Mode” section for details on configuring the beacon mode for any interface.

Configuring Autonegotiation

By default, autonegotiation is enabled all Gigabit Ethernet interface. You can enable or disable autonegotiation for a specified Gigabit Ethernet interface. When autonegotiation is enabled, the port automatically detects the speed or pause method, and duplex of incoming signals based on the link partner. You can also detect link up conditions using the autonegotiation feature.

To configure autonegotiation, follow these steps:

Command
Purpose

Step 1

switch# config terminal

switch(config)#

Enters configuration mode.

Step 2

switch(config)# interface gigabitethernet 2/2

switch(config-if)#

Enters the interface configuration mode on the Gigabit Ethernet interface (slot 2, port 2).

Step 3

switch(config-if)# switchport auto-negotiate

Enables autonegotiation for this Gigabit Ethernet interface (default).

switch(config-if)# no switchport auto-negotiate

Disables autonegotiation for this Gigabit Ethernet interface.


Note When using DS-SFP-GE-T (copper SFPs) on Gigabit Ethernet interfaces in a DS-X9316-SSNK9 module, auto-negotiation should be disabled.


Configuring the MTU Frame Size

You can configure the interfaces on a switch to transfer large (or jumbo) frames on a port. The default IP maximum transmission unit (MTU) frame size is 1500 bytes for all Ethernet ports. By configuring jumbo frames on a port, the MTU size can be increased up to 9000 bytes.


Note The minimum MTU size is 576 bytes.



Tip MTU changes are disruptive, all FCIP links and iSCSI sessions flap when the software detects a change in the MTU size.


You do not need to explicitly issue the shutdown and no shutdown commands.

To configure the MTU frame size, follow these steps:

Command
Purpose

Step 1

switch# config terminal

switch(config)#

Enters configuration mode.

Step 2

switch(config)# interface gigabitethernet 2/2

switch(config-if)#

Enters the interface configuration mode on the Gigabit Ethernet interface (slot 2, port 2).

Step 3

switch(config-if)# switchport mtu 3000

Changes the MTU size to 3000 bytes. The default is 1500 bytes.

Configuring Promiscuous Mode

You can enable or disable promiscuous mode on a specific Gigabit Ethernet interface. By enabling the promiscuous mode, the Gigabit Ethernet interface receives all the packets and the software then filters and discards the packets that are not destined for that Gigabit Ethernet interface.

To configure the promiscuous mode, follow these steps:

Command
Purpose

Step 1

switch# config terminal

switch(config)#

Enters configuration mode.

Step 2

switch(config)# interface gigabitethernet 2/2

switch(config-if)#

Enters the interface configuration mode on the Gigabit Ethernet interface (slot 2, port 2).

Step 3

switch(config-if)# switchport promiscuous-mode on

Enables promiscuous mode for this Gigabit Ethernet interface. The default is off .

switch(config-if)# switchport promiscuous-mode off

Disables (default) promiscuous mode for this Gigabit Ethernet interface.

switch(config-if)# no switchport promiscuous-mode

Disables (default) the promiscuous mode for this Gigabit Ethernet interface.

Verifying Gigabit Ethernet Connectivity

Once the Gigabit Ethernet interfaces are connected with valid IP addresses, verify the interface connectivity on each switch. Ping the IP host using the IP address of the host to verify that the static IP route is configured correctly.


Note If the connection fails, verify the following, and ping the IP host again:
- The IP address for the destination (IP host) is correctly configured.
- The host is active (powered on).
- The IP route is configured correctly.
- The IP host has a route to get to the Gigabit Ethernet interface subnet.
- The Gigabit Ethernet interface is in the up state.


Use the ping command to verify the Gigabit Ethernet connectivity (see Example 46-1). The ping command sends echo request packets out to a remote device at an IP address that you specify (see the “Using the ping and ping ipv6 Commands” section).

Use the show interface gigabitethernet command to verify if the Gigabit Ethernet interface is up.

Example 46-1 Verifying Gigabit Ethernet Connectivity

switch# ping 10.100.1.25
PING 10.100.1.25 (10.100.1.25): 56 data bytes
64 bytes from 10.100.1.25: icmp_seq=0 ttl=255 time=0.1 ms
64 bytes from 10.100.1.25: icmp_seq=1 ttl=255 time=0.1 ms
64 bytes from 10.100.1.25: icmp_seq=2 ttl=255 time=0.1 ms
--- 10.100.1.25 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 0.1/0.1/0.1 ms
 

VLANs

This section describes virtual LAN (VLAN) support in Cisco MDS NX-OS and includes the following topics:

About VLANs for Gigabit Ethernet

Virtual LANs (VLANs) create multiple virtual Layer 2 networks over a physical LAN network. VLANs provide traffic isolation, security, and broadcast control.

Gigabit Ethernet ports automatically recognize Ethernet frames with IEEE 802.1Q VLAN encapsulation. If you need to have traffic from multiple VLANs terminated on one Gigabit Ethernet port, configure subinterfaces—one for each VLAN.


Note If the IPS module or MPS-14/2 module is connected to a Cisco Ethernet switch, and you need to have traffic from multiple VLANs coming to one IPS port, verify the following requirements on the Ethernet switch:
- The Ethernet switch port connected to the IPS module or MPS-14/2 module is configured as a trunking port.
- The encapsulation is set to 802.1Q and not ISL, which is the default.


Use the VLAN ID as a subscription to the Gigabit Ethernet interface name to create the subinterface name (the <slot-number>/<port-number>.<VLAN-ID> ).

Configuring the VLAN Subinterface

To configure a VLAN subinterface (VLAN ID), follow these steps:

Command
Purpose

Step 1

switch# config terminal

switch(config)#

Enters configuration mode.

Step 2

switch(config)# interface gigabitethernet 2/2.100

switch(config-if)#

Specifies the subinterface on which 802.1Q is used (slot 2, port 2, VLAN ID 100).

Note The subinterface number, 100 in this example, is the VLAN ID. The VLAN ID ranges from 1 to 4093.

Step 3

switch(config-if)# ip address 10.1.1.101 255.255.255.0

Enters the IPv4 address (10.1.1.100) and subnet mask (255.255.255.0) for the Gigabit Ethernet interface.

Step 4

switch(config-if)# no shutdown

Enables the interface.

Interface Subnet Requirements

Gigabit Ethernet interfaces (major), subinterfaces (VLAN ID), and management interfaces (mgmt 0) can be configured in the same or different subnet depending on the configuration (see Table 46-1 ).

 

Table 46-1 Subnet Requirements for Interfaces

Interface 1
Interface 2
Same Subnet
Allowed
Notes

Gigabit Ethernet 1/1

Gigabit Ethernet 1/2

Yes

Two major interfaces can be configured in the same or different subnets.

Gigabit Ethernet 1/1.100

Gigabit Ethernet 1/2.100

Yes

Two subinterfaces with the same VLAN ID can be configured in the same or different subnets.

Gigabit Ethernet 1/1.100

Gigabit Ethernet 1/2.200

No

Two subinterfaces with different VLAN IDs cannot be configured in the same subnet.

Gigabit Ethernet 1/1

Gigabit Ethernet 1/1.100

No

A subinterface cannot be configured on the same subnet as the major interface.

mgmt0

Gigabit Ethernet 1/1.100

No

The mgmt0 interface cannot be configured in the same subnet as the Gigabit Ethernet interfaces or subinterfaces.

mgmt0

Gigabit Ethernet 1/1

No


Note The configuration requirements in Table 46-1 also apply to Ethernet PortChannels.


Configuring Static IPv4 Routing

To configure static IPv4 routing (see Figure 46-1) through the Gigabit Ethernet interface, follow these steps:

Command
Purpose

Step 1

switch# config terminal

switch(config)#

Enters configuration mode.

Step 2

switch(config)# ip route 10.100.1.0 255.255.255.0 10.1.1.1

switch(config-if)#

Enters the IP subnet (10.100.1.0 255.255.255.0) of the IP host and configures the next hop 10.1.1.1, which is the IPv4 address of the router connected to the Gigabit Ethernet interface.

Displaying the IPv4 Route Table

The ip route interface command takes the Gigabit Ethernet interface as a parameter and returns the route table for the interface. See Example 46-2.

Example 46-2 Displays the IP Route Table

switch# show ips ip route interface gig 8/1
Codes: C - connected, S - static
No default gateway
C 10.1.3.0/24 is directly connected, GigabitEthernet8/1
 

Connected (C) identifies the subnet in which the interface is configured (directly connected to the interface). Static (S) identifies the static routes that go through the router.

IPv4-ACLs

This section describes the guidelines for IPv4 access control lists (IPv4-ACLs) and how to apply them to Gigabit Ethernet interfaces.

This section includes the following topics:


Note For information on creating IPv4-ACLs, see Chapter35, “Configuring IPv4 and IPv6 Access Control Lists”


Gigabit Ethernet IPv4-ACL Guidelines

Follow these guidelines when configuring IPv4-ACLs for Gigabit Ethernet interfaces:

  • Only use Transmission Control Protocol (TCP) or Internet Control Message Protocol (ICMP).

Note Other protocols such as User Datagram Protocol (UDP) and HTTP are not supported in Gigabit Ethernet interfaces. Applying an ACL that contains rules for these protocols to a Gigabit Ethernet interface is allowed but those rules have no effect.


  • Apply IPv4-ACLs to the interface before you enable an interface. This ensures that the filters are in place before traffic starts flowing.
  • Be aware of the following conditions:

If you use the log-deny option, a maximum of 50 messages are logged per second.

The established option is ignored when you apply IPv4-ACLs containing this option to Gigabit Ethernet interfaces.

If an IPv4-ACL rule applies to a pre-existing TCP connection, that rule is ignored. For example if there is an existing TCP connection between A and B and an IPv4-ACL which specifies dropping all packets whose source is A and destination is B is subsequently applied, it will have no effect.


Tip If IPv4-ACLs are already configured in a Gigabit Ethernet interface, you cannot add this interface to an Ethernet PortChannel group. ““Configuring IPv4 and IPv6 Access Control Lists,” for information on configuring IPv4-ACLs.


Applying IPv4-ACLs on Gigabit Ethernet Interfaces

To apply an IPv4-ACL on a Gigabit Ethernet interface, follow these steps:

Command
Purpose

Step 1

switch# config t

Enters configuration mode.

Step 2

switch(config)# interface gigabitethernet 3/1

switch(config-if)#

Configures a Gigabit Ethernet interface (3/1).

Step 3

switch(config-if)# ip access-group SampleName

Applies the IPv4-ACL SampleName on Gigabit Ethernet 3/1 for both ingress and egress traffic (if the association does not exist already).

Step 4

switch(config-if)# ip access-group SampleName1 in

Applies the IPv4-ACL SampleName on Gigabit Ethernet 3/1 for ingress traffic.

switch(config-if)# ip access-group SampleName2 out

Applies the IPv4-ACL SampleName on Gigabit Ethernet 3/1 for egress traffic (if the association does not exist already).

ARP Cache

Cisco MDS NX-OS supports ARP cache for Gigabit Ethernet interface configured for IPv4. This section includes the following topics:

Displaying ARP Cache

You can display the ARP cache on Gigabit Ethernet interfaces.


Note Use the physical interface, not the subinterface, for all ARP cache commands.


Use the show ips arp interface gigabitethernet command to display the ARP cache on the Gigabit Ethernet interfaces. This command takes the Ethernet interface as a parameter and returns the ARP cache for that interface. See Example 46-3.

Example 46-3 Displays ARP Caches

switch# show ips arp interface gigabitethernet 7/1
Protocol Address Age (min) Hardware Addr Type Interface
Internet 20.1.1.5 3 0005.3000.9db6 ARPA GigabitEthernet7/1
Internet 20.1.1.10 7 0004.76eb.2ff5 ARPA GigabitEthernet7/1
Internet 20.1.1.11 16 0003.47ad.21c4 ARPA GigabitEthernet7/1
Internet 20.1.1.12 6 0003.4723.c4a6 ARPA GigabitEthernet7/1
Internet 20.1.1.13 13 0004.76f0.ef81 ARPA GigabitEthernet7/1
Internet 20.1.1.14 0 0004.76e0.2f68 ARPA GigabitEthernet7/1
Internet 20.1.1.15 6 0003.47b2.494b ARPA GigabitEthernet7/1
Internet 20.1.1.17 2 0003.479a.b7a3 ARPA GigabitEthernet7/1
...
 

Clearing ARP Cache

The ARP cache can be cleared in two ways: clearing just one entry or clearing all entries in the ARP cache.

Use the clear ips arp command to clear the ARP cache. See Example 46-4 and Example 46-5.

Example 46-4 Clearing One ARP Cache Entry

switch# clear ips arp address 10.2.2.2 interface gigabitethernet 8/7
arp clear successful
 

Example 46-5 Clearing All ARP Cache Entries

switch# clear ips arp interface gigabitethernet 8/7
arp clear successful
 

Displaying IPv4 Statistics

Use the show ips stats ip interface gigabitethernet to display and verify IP v4 statistics. This command takes the main Ethernet interface as a parameter and returns the IPv4 statistics for that interface. See Example 46-6.


Note Use the physical interface, not the subinterface, to displayIPv4 statistics.


Example 46-6 Displays IPv4 Statistics

switch# show ips stats ip interface gigabitethernet 4/1
Internet Protocol Statistics for port GigabitEthernet4/1
168 total received, 168 good, 0 error
0 reassembly required, 0 reassembled ok, 0 dropped after timeout
371 packets sent, 0 outgoing dropped, 0 dropped no route
0 fragments created, 0 cannot fragment
 

Default Settings

Table 46-2 lists the default settings for IPv4 parameters.

 

Table 46-2 Default IPv4 Parameters

Parameters
Default

IPv4 MTU frame size

1500 bytes for all Ethernet ports.

Autonegotiation

Enabled.

Promiscuous mode

Disabled.