Cisco ME3400 notes

The current CCIE SP exams focuses on the metro line of ME3400 switches. For the most part its just another switch. There are a couple of differences which I wanted to put here for my own notes. I’ve spent a lot of time on my L3, so I really need more of these L2 notes.

For references I’m doing this all on a ME-3400G-2CS-A running.

Switch#sh ver | include IOS
Cisco IOS Software, ME340x Software (ME340x-METROIPACCESS-M), Version 12.2(52)SE, RELEASE SOFTWARE

This switch at the start has a blank config.

  • There are three port types: UNI, NNI, and ENI. By default this particular model comes configured like so:
Switch#sh port-type
Port      Name               Vlan       Port Type
--------- ------------------ ---------- ----------------------------
Gi0/1                        1          User Network Interface           (uni)
Gi0/2                        1          User Network Interface           (uni)
Gi0/3                        1          Network Node Interface           (nni)
Gi0/4                        1          Network Node Interface           (nni)

Out of interest, the two default UNI ports are administratively shut, while the NNIs are not:

Switch#sh int status

Port      Name               Status       Vlan       Duplex  Speed Type
Gi0/1                        disabled     1            auto   auto Not Present
Gi0/2                        disabled     1            auto   auto Not Present
Gi0/3                        notconnect   1            auto   auto Not Present
Gi0/4                        notconnect   1            auto   auto Not Present

Let’s no shut interface gi0/1 and stick it in vlan 3:

Switch(config)#int gi0/1
Switch(config-if)#no shut
Switch(config-if)#switch access vlan 3
% Access VLAN does not exist. Creating vlan 3
Switch(config-if)#end
  • Notice that STP and CDP do not run on this uni port:
Switch#sh span interface gi0/1 detail
no spanning tree info available for GigabitEthernet0/1

Switch#show cdp int
GigabitEthernet0/3 is down, line protocol is down
  Encapsulation ARPA
  Sending CDP packets every 60 seconds
  Holdtime is 180 seconds
GigabitEthernet0/4 is down, line protocol is down
  Encapsulation ARPA
  Sending CDP packets every 60 seconds
  Holdtime is 180 seconds
  • UNI supports etherchannel on only, no LACP or PAgP:
Switch(config-if)#channel-group 1 mode ?
  on  Enable Etherchannel only

Let’s change this to an NNI port to see what options we get:

Switch(config-if)#int gi0/1
Switch(config-if)#port-type nni
Switch(config-if)#channel-group 2 mode ?
  active     Enable LACP unconditionally
  auto       Enable PAgP only if a PAgP device is detected
  desirable  Enable PAgP unconditionally
  on         Enable Etherchannel only
  passive    Enable LACP only if a LACP device is detected
Switch#show cdp interface
GigabitEthernet0/1 is up, line protocol is up
  Encapsulation ARPA
  Sending CDP packets every 60 seconds
  Holdtime is 180 seconds
GigabitEthernet0/3 is down, line protocol is down
  Encapsulation ARPA
  Sending CDP packets every 60 seconds
  Holdtime is 180 seconds
GigabitEthernet0/4 is down, line protocol is down
  Encapsulation ARPA
  Sending CDP packets every 60 seconds
  Holdtime is 180 seconds

 Switch#sh span int gi0/1 detail
 Port 56 (Port-channel1) of VLAN0003 is designated forwarding
   Port path cost 19, Port priority 128, Port Identifier 128.56.
   Designated root has priority 32771, address 10bd.1804.7900
   Designated bridge has priority 32771, address 10bd.1804.7900
   Designated port id is 128.56, designated path cost 0
   Timers: message age 0, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   Link type is point-to-point by default
   BPDU: sent 30, received 0
  • ENI acts like a UNI port, but gives you STP, CDP, and LACP/PAgP. However all of this is disabled by default
Switch(config)#int gi0/1
Switch(config-if)#port-type eni
Switch(config-if)#channel-group 3 mode ?
  active     Enable LACP unconditionally
  auto       Enable PAgP only if a PAgP device is detected
  desirable  Enable PAgP unconditionally
  on         Enable Etherchannel only
  passive    Enable LACP only if a LACP device is detected

Switch(config-if)#cdp ?
  enable  Enable CDP on interface

Switch(config-if)#spanning-tree
  • The spanning-tree mode is rapid by default. But this can be changed. As noted before I have not changed the mode of spanning tree yet:
Switch#sh span | include protocol
  Spanning tree enabled protocol rstp

This can be changed:

Switch(config)#spanning-tree mode ?
  mst         Multiple spanning tree mode
  pvst        Per-Vlan spanning tree mode
  rapid-pvst  Per-Vlan rapid spanning tree mode
  • VTP is not supported:
Switch#sh vtp ?
% Unrecognized command
  • DTP is not supported. Either you run a static trunk or static access port. No DTP (Which I usually disable anyway)
Switch#sh int gi0/1 switchport  | include Nego
Negotiation of Trunking: Off
  • UNI and ENI ports cannot speak to each other by default. Only to an NNI port. This is similar to private-vlans (in particular, isolated private-vlans)
  • Note that private-vlans are still supported as a separate technology.

To view the type, check show vlan uni-vlan. When its empty its the default ‘isolated’ type (very annoying that it doesn’t show:

Switch#sh vlan uni-vlan

VLAN Type              Ports
---- ----------------- -------------------------------------------------------

You can change this to act like a community private vlan. This is so ENI/UNI ports in the same vlan can speak to each other, as well as the NNI port in the same vlan:

Switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)#vlan 3
Switch(config-vlan)#uni-vlan community
Switch(config-vlan)#end
Switch#
*Mar  1 00:33:02.706: %SYS-5-CONFIG_I: Configured from console by console
Switch#
Switch#sh vlan uni-vlan

VLAN Type              Ports
---- ----------------- -------------------------------------------------------
3    UNI community     Gi0/1
  • ISL is not supported. i.e. when configuring a trunk, you just need switchport mode trunk. No need to specify which type when there is only a single type.
  • These are the SDM types with this particular model:
Switch(config)#sdm prefer ?
  default             Default bias
  dual-ipv4-and-ipv6  Support both IPv4 and IPv6
  layer-2             No routing
Switch#sh sdm prefer
 The current template is "default" template.
 The selected template optimizes the resources in
 the switch to support this level of features for
 8 routed interfaces and 1024 VLANs.

  number of unicast mac addresses:                  5K
  number of IPv4 IGMP groups + multicast routes:    1K
  number of IPv4 unicast routes:                    9K
    number of directly-connected IPv4 hosts:        5K
    number of indirect IPv4 routes:                 4K
  number of IPv4 policy based routing aces:         0.5K
  number of IPv4/MAC qos aces:                      0.5K
  number of IPv4/MAC security aces:                 1K
  • MPLS is not supported:
Switch(config)#mpls ?
% Unrecognized command
  • MLS QoS is not supported, but MQC QoS is supported.
  • Pretty much everything else is like a regular 3560/3750 switch

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