dladm is the admin utility for Data-Link Interface which helps to display informarthe like Link Status (UP/DOWN), Speed, Duplex, MTU, VLAN Tagged and crucially statistics of network traffic on each of the interfaces historically as well as in real time. dladm can also configure and admin Link Aggregation on multiple NICs which we will not focus here.

Show Link Status/Speed/Duplex

# dladm show-dev
nxge0           link: down      speed: 0     Mbps       duplex: unknown
nxge1           link: down      speed: 0     Mbps       duplex: unknown
nxge2           link: up        speed: 1000  Mbps       duplex: full
nxge3           link: up        speed: 1000  Mbps       duplex: full

As you can see above the “show-dev” option lists all the network interfaces with Link Status (UP/DOWN), current speed in Mbps and Duplex (Half/Full)

Show Link Status

# dladm show-link
nxge0           type: non-vlan  mtu: 1500       device: nxge0
nxge1           type: non-vlan  mtu: 1500       device: nxge1
nxge2           type: non-vlan  mtu: 1500       device: nxge2
nxge3           type: non-vlan  mtu: 1500       device: nxge3

Here “show-link” option reveals the MTU and the VLAN tagging detail on each of the interfaces on the system.

Show Stats of all Interfaces for all time

# dladm show-dev -s
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge0           0         0           0       0         0           0
nxge1           0         0           0       0         0           0
nxge2           179625752557169463759657      581104982 3964684165410
nxge3           22240891  1834257868  0       5198483   395084708   0

The “-s” option along with “show-dev” or “show-link” displays network traffic statistics including Input/Output packets, input/output errors.

Stats in real-time

To show the stats of a particular interface in real-time use the “-i” option which is the interval in seconds. The first line shows again historic stats and later on the real-time information for every “n” seconds (5 seconds in our example)

# dladm show-link -s -i 5 nxge2
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge2           179637824757173944575957      581119516 3964706801670
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge2           961       319105             0       150       17874       0
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge2           887       263850             0       117       16505       0

If we fail to mention the interface then it takes the default interface (1st in the list). As you can see from the example below, we see stats for nxge0 which is not connected.

# dladm show-link -s -i 5
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge0           0         0           0       0         0           0
ipackets  rbytes         ierrors opackets        obytes      oerrors
nxge0           0         0           0       0         0           0

IPMP is mostly used to provide resilience with network connections wherein a Sun Solaris Server with multiple NICs can be configured such that if the primary NIC fails it automatically failover to the secondary NIC on the system. Also, if it is a multi-switch environment then each Network Interface participating in IPMP can be connection to two different switches such that a network connection failure due to a NIC failure or a switch failure can be avoided.

To configure IPMP for resiliency we need to have

1. Virtual IP Address

2. Test IP Address for each NIC.

The Virtual IP is the actual Data IP and the test IPs are the ones used by IPMP to probe a remote target system to check connectivity. The test IP interfaces are marked as “deprecated” which indicates that this IP should be used by applications for any network data transfer. The NICs doesn’t have to be of the same make or have to be the same speed (10/100/1000Mbps). However, they should be of the same kind (Ethernet here)

In our configuration,

192.168.1.100 – Virtual IP

192.168.1.101 – Test IP for ce0 (NIC1)

192.168.1.102 – Test IP for ce1 (NIC2)

appserver – Hostname

appserver-ce0 – Hostname for IP on ce0 interface

appserver-ce1 – Hostname for IP on ce1 interface

Add Host Entries in /etc/hosts

Let’s start with adding the hosts entries for the IP addresses in the /etc/hosts file.

# IPMP group appserver-ipmp
127.0.0.1       localhost
192.168.1.100  appserver        loghost
192.168.1.101  appserver-ce0    loghost
192.168.1.102  appserver-ce1    loghost

Create hostname.ce* files

For every interface on the system create a hostname.ce* file. For us, create the files

hostname.ce0 & hostname.ce1

Edit hostname.ce0

Add the following on the hostname.ce0 file. This is the primary or master interface of the IPMP Pair

appserver-ce0 netmask + broadcast + group appserver-ipmp deprecated -failover up\

addif appserver netmask + broadcast + failover up

Edit hostname.ce1

Add the following on the hostname.ce1 file. This is the secondary or slave interface of the IPMP Pair

appserver-ce1 netmask + broadcast + group appserver-ipmp deprecated \
-failover standby up

where

netmask – sets default netmask values

broadcast – sets default broadcast address

-failover  – indicates that the test IPs should not be failed over

deprecated – indicates that the interface should not be used for data transfer

Now, the configuration is complete and an ifconfig output should look like as follows:

root@ appserver:/$
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
inet 127.0.0.1 netmask ff000000
ce0: flags=9040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER> mtu 1500 index 2
inet 192.168.1.101 netmask ffffff00 broadcast 192.168.1.255
groupname appserver-ipmp
ether 0:xx:xx:xx:xx:x
ce0:1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
inet 192.168.1.100 netmask ffffff00 broadcast 192.168.1.255
ce1: flags=69040843<UP,BROADCAST,RUNNING,MULTICAST,DEPRECATED,IPv4,NOFAILOVER,STANDBY,INACTIVE> mtu 1500 index 3
inet 192.168.1.102 netmask ffffff00 broadcast 192.168.1.255
groupname appserver-ipmp
ether 0:xx:xx:xx:xx:x

You can see a new virtual interface for “ce0″ is being created as “ce0:1″ and the  “ce1″ interface status is UP but INACTIVE. Indicating it is up and participating in the IPMP but is  as a standby. Test by pinging the device continously from a remote PC and unplugging the active NIC and you should see no packets drop. Reverse the tests and check if it works OK. Also, if you are on the console, you can see the live link messages (check later from /var/adm/messages)