Category Archives for "DataCenter Fun"

HP Network Simulator

Is released by HP the new version of simulator for network devices (Switches and Routers) based on Comware 7 OS. This software is called HP Network Simulator.

I’m very happy about that because I have waited for a long time to run some commands and features in a lab environment.

The simulator is based on Cowmare 7 ( most commands are very similar to OS 5 version)

List below the link for download, inside there are some instructions for installing and configuring the topology that you wish.

HP Network Simulator

Despite of the software working on GUI mode, the topology design must be made via text in a configuration file (also explained in the software manual).

Enjoy it, share and comment. It’s a good time to celebrate.

If the link is broken, please leave a comment.

HP Comware-based Switches – Link Aggregation

The 3Com/HPN/H3C based Switches offers the utilization of interfaces such as Ethernet, Fast Ethernet, GigabitEthernet or TenGigabitEthernet. The Link Aggregation feature allows the gathering of many ports in order to increase the link’s velocity concerning the full duplex communication between the two devices.

In Link-Aggregation mode the ports are utilized in parallel, supporting the bandwith’s growth and expansion, without the need of buying an additional hardware.

For example, we can use four 100Mb ports in each device to form a communication between two switches using 400Mb among them. However, the utilization of redundant enlaces raises the possibility of loops within the network. Link Aggregation avoids the situation which the blocking state or loops, stop the gathered ports, treating them as one single interface. For the STP, SNMP and VLANs the interfaces are treated as one logical link.

Other name used for the Link Aggregation is EtherChannel.

The LACP protocol is part of the 802.3ad specification for Link Aggregation, allowing that switches and servers negotiate the port groups with different manufactures automatically. Both ports should offer constant support to the protocol, so that the Link Aggregation could work correctly.

Some Switch models can utilise the PagP (Cisco) protocol or interface Continue reading

Comware: Configuring QinQ

The QinQ feature (802.1q over 802.1q), also known as Stacked VLAN or VLAN over VLAN, supports the utilization of two 802.1q tags on the same frame Ethernet for VLAN over VLAN traffic – without altering the original TAG.

For the customer perspective it is like the Service Provider has extended the cable or fiber between 2 points. From the Service Provider perspective, it doesn’t matter if the customer is sending a frame ethernet with or without TAG 802.1q, because it will add one more TAG to the header and remove on edge device just the last insert tag.


In a nutshell, the inbound interface configured with QinQ, will add a 802.1q TAG to the frame, even in case if the VLANs were tagged, however on the outbound port, only the last TAG added is removed, keeping the TAG 802.q inserted by the client.


QinQ Comware

With the example above, we shall configure both Switches A and B with one VLAN for each client and configure the customer-connected-interfaces, such as “qinq enable”. As a detail, notice that is important to disable the STP on each interface for the BPDU issues, so the BPDUs will not interfere Continue reading

Utilizing LLDP instead of CDP

In the last years, many vendors of network devices made available in the market equipments with interesting prices and quality that ended transforming the network environment of companies on a scenario that share different models and devices. Despite the fact that there is a seducing cost, unfortunately some property protocols (despite being interesting)  create a barrier of integration among many services or replacement of Switches, Routers,etc.

In order to mapping and discovering neighbor devices in a network with controlled environment  and with IP telephony, the Cisco suggest the CDP utilization, but unfortunately the protocol is property of  Cisco, limiting its utilization with other models and equipment.

The LLDP protocol is an open standard to discovery devices that are neighbors, with similarly as CDP, including the utilization of features for the VLAN voice.

With the tests below, we activate the LLDP in a Cisco 3750 Switch and a HPN 12500 Switch.



Cisco3750(config)# lldp run
!Run LLDP on Cisco Switch 

[HPN12K] lldp enable
! Run LLDP on HP Comware-based Switch

To visualize the mapping of neighbors with Cisco we can use:

Cisco3750#show lldp neighbors
Capability codes:
    (R) Router, (B) Bridge, (T) Telephone, (C) DOCSIS Cable Device
    (W) WLAN Access Point, (P)  Continue reading

HP Comware-based Switches – Configuring filters for BPDU (bpdu-filtering)

The Spanning-tree protocol sends messages every two second in order to keep the LAN stability, protecting the topology from physical loops (blocking the logical loop) and providing high availability in case of any switch fail.

For that matter, the Switches exchange messages called BDPUs which are utterly important for the correct functioning of the network described as above.

There are scenarios when is necessary to deactivate the protocol within a specific interface, utilizing other protocols and features of high availability such as RRPP, Smart-Link, Monitor-Link, etc or when also the Switch needs to transport the information in tunnel form (transparent), for example, QinQ.

In client-sharing environments, it is not recommended that the network alteration be advised for all  Swtiches that do not belong to that particular network and have the same Switch in common, for example, Service Provider and Data Center.

The main question in this scenario of BPDU filtering is to certify that the network does not have any sort of loop that can cause a disaster for the Network Engineer’s project.

Certifying those questions, the HP Comware based Switches carry the following commands, that may help  finding a solution:

Interface gigabitethernet 1/0/1
stp disable
! Deactivating  STP only on  Continue reading

3Com / H3C / HP Comware based Switches – Edged-port + BPDU Protection

Today we’ll comment on the two features that work as a complement to the Spanning-Tree. The edged-port command gathers many benefits to the STP, for example, the timeout prevention concerning the DHCP process. As for the bpdu-protection, it prevents loop in the “edged” configured ports within the network via HUBs, “Switches HUB”, etc.


The edged-port feature allows the interface to skip the Listening and Learning states of the Spanning-Tree Protocol, setting the ports into the Forwarding state immediately.  The STP’s configuration edged-port enable, forces the interface to ignore the convergence states of the STP, including the notification of topology change messages (TCN messages).

The command must be applied to the access ports connected to servers, workstations, printers, etc.


[Switch]interface gigabitethernet 1/0/1
[Switch-GigabitEthernet1/0/1]stp edged-port enable
[Switch]interface gigabitethernet 1/0/2
[Switch-GigabitEthernet1/0/2]stp edged-port enable

PS: When a port is configured as a edged-port receives a BPDU, the interface will return to participate on the STP like any other interface.
PS:An Edged-port send BPDUs normally. The edged-port feature is also known as Portfast.

 BPDU Protection

The utilization of the edged-port feature is restricted to ports connected to the final equipment such as servers and workstations. Continue reading

Comware: Port Link-mode Bridge vs Port Link-mode Route

Some HP L3 Switches Comware based, brings the concept of “switchports” as Bridge and Route mode.

The Bridge mode (port link-mode bridge) works the same way that any other access Switches.

When using Route mode (port link-mode route) the port is converted into a layer 3 interface, which need an IP address.  All STP messages will be ignored.


interface GigabitEthernet4/0/1
port link-mode route
ip address
interface GigabitEthernet4/0/2
port link-mode bridge
port link-type access
port access vlan 2


Comware: Clearing an Interface Configuration

HP released the “default” command on interface-view in the latest version of Comware in order to restore to default configuration of an interface.

This command is useful when you want to clear an interface configuration and reuse the interface for some other task. Normally you would need to issue the “undo” command for each line.

Following below the configuration (the command was tested on HP 7500 Switches Release 6626P02)


[HP-GigabitEthernet1/0/1] display this
! checking interface configuration before clean up
interface GigabitEthernet1/0/1
port link-mode bridge
port link-type trunk
port trunk permit vlan all

This command will restore the default settings. Continue? [Y/N]:y
! Setup default command on interface
[HP-GigabitEthernet1/0/1]display this
interface GigabitEthernet1/0/1
port link-mode bridge

See you soon :)

Comware: STP disable

As default, STP and other features are disable on some HP device based on Comware. In this case it is important to always check the Spanning-Tree Protocol status before include a device in a network in production. And if necessary enable it. ;)


[Switch] display stp
Protocol Status :disabled
Protocol Std. :IEEE 802.1s
Version :3
Bridge-Prio. :32768
MAC address :000f-e203-0200
Max age(s) :20
Forward delay(s) :15
Hello time(s) :2
Max hops :20
! Identify that STP is enabled on Switch

[Switch]stp enable
%Jun 18 16:21:10:253 2012 Switch MSTP/6/MSTP_ENABLE: STP is now
enabled on the device.
! enabling Spanning-Tree

See you soon.