Posts tagged ERS5520

802.1Q VLAN Tagging on a Cisco Catalyst 3750-E

14
January 29, 2011
by Michael McNamara in ,

In the two previous posts I covered how to create multiple VLANs, trunk those VLANs between multiple stackable Avaya Ethernet Routing Switches utilizing Multi-Link Trunking and how to create Layer 3 IP interfaces to be used for routing IP packets between those VLANs.

In this post I thought I would expand the network topology of my previous two posts to include a Cisco Catalyst 3750-E. I’ll specifically cover how to trunk (bridge) multiple VLANs between a stackable Avaya Ethernet Routing Switch and the Cisco Catalyst 3750-E and how to configure multiple interfaces in a Link Aggregation Group (LAG) utilizing LACP similar to Avaya’s proprietary MLT feature.

Avaya Ethernet Routing Switch 4548

enable
config t

Let’s start by making ports 45 and 46 trunk ports which will utilize 802.1Q tagging;

vlan ports 45,46 tagging tagAll

Let’s add the VLANs we wish to bridge across the trunk ports;

vlan members add 1 45,46
vlan members add 100 45,46
vlan members add 200 45,46

Now we’ll enable LACP on ports 45 and 46 using the same LACP key which will automatically create the LAG;

interface fastEthernet 45
lacp key 10
lacp mode active
lacp timeout-time short
lacp aggregation enable
exit

interface fastEthernet 46
lacp key 10
lacp mode active
lacp timeout-time short
lacp aggregation enable
exit

Avaya Ethernet Routing Switch 4548 – Show Commands

4548GT-PWR#show lacp port 45,46
Admin Oper         Trunk Partner
Port Priority Lacp    A/I Timeout Key   Key   AggrId Id    Port    Status
---- -------- ------- --- ------- ----- ----- ------ ----- ------- ------
45   32768    Active  A   Short   10    12298 8224   32    302     Active
46   32768    Active  A   Short   10    12298 8224   32    303     Active

4548GT-PWR#show mac-address-table
Mac Address Table Aging Time: 300
Number of addresses: 26

   MAC Address    Vid  Source         MAC Address    Vid  Source
----------------- ---- -------     ----------------- ---- -------
00-02-B3-CB-77-A2    1 Port:19     00-04-61-9E-46-7E    1 Port:21
00-0C-29-64-33-F9    1 Port:19     00-0C-29-A5-CB-54    1 Port:19
00-0F-20-95-38-D5    1 Port:11     00-18-01-EA-F4-45    1 Port: 1
00-1C-11-6B-DC-6B    1 Port: 1     00-1C-11-6D-15-27    1 Port: 1
00-1C-11-6D-15-DC    1 Port: 1     00-1E-7E-7C-2C-00    1
00-1E-7E-7C-2C-40    1             00-1F-0A-CE-BC-01    1 Trunk:1
00-1F-0A-CE-BC-40    1 Trunk:1     00-1F-D0-D0-BE-2D    1 Port:17
00-23-EE-96-AA-21    1 Port: 1     00-24-B5-F6-94-02    1 Trunk:1
00-64-40-CF-4D-AD    1 Trunk:32    00-64-40-CF-4D-AE    1 Trunk:32
00-64-40-CF-4D-C0    1 Trunk:32    00-0A-E4-76-9C-C8    2 Port:44
00-24-DC-DF-0D-08    2 Port:43     00-A0-F8-5E-CE-BC    2 Port:39
00-1F-0A-CE-BC-41  100 Trunk:1     00-24-7F-99-84-70  100 Port:25
00-64-40-CF-4D-AD  100 Trunk:32    00-1E-CA-F3-1D-B4  200 Port:26
00-1F-0A-CE-BC-43  200 Trunk:1     00-64-40-CF-4D-AD  200 Trunk:32

4548GT-PWR#show mlt
Id Name             Members                Bpdu   Mode           Status  Type
-- ---------------- ---------------------- ------ -------------- ------- ------
1  MLT_to_ERS5520   47-48                  All    Basic          Enabled Trunk
2  Trunk #2         NONE                   All    Basic          Disabled
3  Trunk #3         NONE                   All    Basic          Disabled
4  Trunk #4         NONE                   All    Basic          Disabled
5  Trunk #5         NONE                   All    Basic          Disabled
6  Trunk #6         NONE                   All    Basic          Disabled
7  Trunk #7         NONE                   All    Basic          Disabled
8  Trunk #8         NONE                   All    Basic          Disabled
9  Trunk #9         NONE                   All    Basic          Disabled
10 Trunk #10        NONE                   All    Basic          Disabled
11 Trunk #11        NONE                   All    Basic          Disabled
12 Trunk #12        NONE                   All    Basic          Disabled
13 Trunk #13        NONE                   All    Basic          Disabled
14 Trunk #14        NONE                   All    Basic          Disabled
15 Trunk #15        NONE                   All    Basic          Disabled
16 Trunk #16        NONE                   All    Basic          Disabled
17 Trunk #17        NONE                   All    Basic          Disabled
18 Trunk #18        NONE                   All    Basic          Disabled
19 Trunk #19        NONE                   All    Basic          Disabled
20 Trunk #20        NONE                   All    Basic          Disabled
21 Trunk #21        NONE                   All    Basic          Disabled
22 Trunk #22        NONE                   All    Basic          Disabled
23 Trunk #23        NONE                   All    Basic          Disabled
24 Trunk #24        NONE                   All    Basic          Disabled
25 Trunk #25        NONE                   All    Basic          Disabled
26 Trunk #26        NONE                   All    Basic          Disabled
27 Trunk #27        NONE                   All    Basic          Disabled
28 Trunk #28        NONE                   All    Basic          Disabled
29 Trunk #29        NONE                   All    Basic          Disabled
30 Trunk #30        NONE                   All    Basic          Disabled
31 Trunk #31        NONE                   All    Basic          Disabled
32 Trunk #32        45-46                  Single DynLag/Basic   Enabled Trunk

You might be looking at the output above and asking yourself what’s “Trunk 32″? Let me provide some quick background. You can have a total of 32 MLT/LAG trunks on a stackable Avaya Ethernet Routing Switch. When you create LACP trunks the switch automatically creates a LAG in the MLT table dynamically from the bottom up. While in the previous post I created “Trunk 1″ by trunking ports 47 and 48 together (see above), in this post I’ve created an LACP trunk on ports 45 and 46 which will be reported it the switch as “Trunk 32″. You can also see it in the MAC/FDB table above.

Cisco Catalyst 3750-E

enable
config t

Let’s give the switch an IP address in VLAN 1 for management;

vlan 1
ip address 192.168.1.25 255.255.255.0
no shut
exit

Let’s create VLAN 100 and VLAN 200 on the switch;

vlan 100
name "192-168-100-0/24"
exit
vlan 200
name "192-168-200-0/24"
exit

Let’s add the appropriate edge ports to each VLAN;

interface range gigabitEthernet 1/0/1-12
switchport access vlan 1
exit
interface range gigabitEthernet 1/0/13-24
switchport access vlan 100
exit
interface range gigabitEthernet 1/0/24-36
switchport access vlan 200
exit

Let’s configure ports 45 and 46 as trunk ports and bond them together in channel-group utilizing LACP;

interface gigabitEthernet 1/0/45
switchport trunk encapsulation dot1q
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active

interface gigabitEthernet 1/0/46
switchport trunk encapsulation dot1q
switchport mode trunk
channel-protocol lacp
channel-group 1 mode active

Cisco Catalyst 3750-E – Show Commands

SW-3750-E#show lacp neighbor
Flags:  S - Device is requesting Slow LACPDUs
F - Device is requesting Fast LACPDUs
A - Device is in Active mode       P - Device is in Passive mode

Channel group 1 neighbors

Partner's information:

LACP port                        Admin  Oper   Port    Port
Port      Flags   Priority  Dev ID          Age    key    Key    Number  State
Gi1/0/45  FA      32768     001e.7e7c.2c00  16s    0x0    0x300A 0x2D    0x3F
Gi1/0/46  FA      32768     001e.7e7c.2c00  27s    0x0    0x300A 0x2E    0x3F

Switch#show mac address-table
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
 All    0100.0ccc.cccc    STATIC      CPU
 All    0100.0ccc.cccd    STATIC      CPU
 All    0180.c200.0000    STATIC      CPU
 All    0180.c200.0001    STATIC      CPU
 All    0180.c200.0002    STATIC      CPU
 All    0180.c200.0003    STATIC      CPU
 All    0180.c200.0004    STATIC      CPU
 All    0180.c200.0005    STATIC      CPU
 All    0180.c200.0006    STATIC      CPU
 All    0180.c200.0007    STATIC      CPU
 All    0180.c200.0008    STATIC      CPU
 All    0180.c200.0009    STATIC      CPU
 All    0180.c200.000a    STATIC      CPU
 All    0180.c200.000b    STATIC      CPU
 All    0180.c200.000c    STATIC      CPU
 All    0180.c200.000d    STATIC      CPU
 All    0180.c200.000e    STATIC      CPU
 All    0180.c200.000f    STATIC      CPU
 All    0180.c200.0010    STATIC      CPU
 All    ffff.ffff.ffff    STATIC      CPU
   1    0004.619e.467e    DYNAMIC     Po1
   1    000c.2964.33f9    DYNAMIC     Po1
   1    000c.29a5.cb54    DYNAMIC     Po1
   1    000f.2095.38d5    DYNAMIC     Po1
   1    0018.01ea.f445    DYNAMIC     Po1
   1    001c.116b.dc6b    DYNAMIC     Po1
   1    001c.116d.1527    DYNAMIC     Po1
   1    001c.116d.15dc    DYNAMIC     Po1
   1    001e.7e7c.2c01    DYNAMIC     Po1
   1    001e.7e7c.2c2d    DYNAMIC     Po1
   1    001e.7e7c.2c2e    DYNAMIC     Po1
   1    001f.d0d0.be2d    DYNAMIC     Po1
   1    0023.ee96.aa21    DYNAMIC     Po1
   1    00a0.f85e.cebd    DYNAMIC     Po1
 100    0024.7f99.84e9    DYNAMIC     Po1
 200    0008.02e4.890a    DYNAMIC     Gi1/0/25
 200    001e.caf3.1db4    DYNAMIC     Po1
Total Mac Addresses for this criterion: 37

You might be asking why didn’t I assign the VLANs to the trunk ports on the Cisco Catalyst 3750-E… well with Cisco switches a trunk port is by default a member of all the VLANs that exist on the switch. So you don’t need to specifically add a VLAN to a trunk port, however, you can override the default behavior by telling the switch to only carry specific VLANs on a specific trunk port – this is called VLAN pruning.

Please feel free to point out any inconsistencies or errors I might have made.

Cheers!

802.1Q VLAN Tagging on an Ethernet Routing Switch

14
January 27, 2011
by Michael McNamara in ,

In my previous post I laid out the basics of how to configure multiple VLANs and enable IP routing on a stackable Avaya Ethernet Routing Switch. In this post I’m going to expand that topic to include trunking (802.1q) those VLANs to a second Ethernet Routing Switch. In this example I’ll add an Ethernet Routing Switch 4548 to the Ethernet Routing Switch 5520 that I had previously configured and deployed. We’ll create a Multi-Link Trunk between the two switches to bridge multiple VLANs across the 802.1q compliant link. Here’s a diagram of what the network should look like when we’re done;

In order to test I’ll move two of the IP phones to the Ethernet Routing Switch 4548 and I’ll use an old laptop to help verify the bridging.

Ethernet Routing Switch 4548

Let’s start with the Ethernet Routing Switch 4548GT-PWR and add the necessary configuration there first;

enable
config t

We start by creating VLAN 100 and VLAN 200 on the Ethernet Routing Switch 4548;

vlan create 100 name "192-168-100-0/24" type port
vlan members remove 1 25,27,29,31,33,35
vlan members add 100 25,27,29,31,33,35
vlan port 25,27,29,31,33,35 pvid 100

vlan create 200 name "192-168-200-0/24" type port
vlan members remove 1 26,28,30,32,34,36
vlan members add 200 26,28,30,32,34,36
vlan port 26,28,30,32,34,36 pvid 200

I’m not going to create a Layer 3 IP interfaces on these VLANs since the Ethernet Routing Switch 5520 is already routing for us. We just want to bridge the frames between the two switches not route them (not in this post anyway). Now let’s configure the ports that will make up the Mulit-Link Trunk;

vlan port 47,48 tagging TagAll
vlan members add 1 47,48
vlan members add 100 47,48
vlan members add 200 47,48
vlan port 47,48 pvid 1

mlt 1 disable
mlt 1 name "MLT_to_ERS5520"
mlt 1 learning disable
mlt 1 member 47,48
mlt 1 enable

That’s pretty much it. We enabled tagging on the uplink/downlink ports, added the necessary VLANs to the ports and then created and enabled a MLT.

Ethernet Routing Switch 4548 – Show Configuration

That should be the configuration for the Ethernet Routing Switch 4548… let’s just have a quick look at the VLANs;

4548GT-PWR(config)#show vlan
Id  Name                 Type     Protocol         User PID Active IVL/SVL Mgmt
--- -------------------- -------- ---------------- -------- ------ ------- ----
1   VLAN #1              Port     None             0x0000   Yes    IVL     Yes
        Port Members: 1-24,47-48
2   VLAN #2              Port     None             0x0000   Yes    IVL     No
        Port Members: 37-46
100 192-168-100-0/24     Port     None             0x0000   Yes    IVL     No
        Port Members: 25,27,29,31,33,35,47-48
200 192-168-200-0/24     Port     None             0x0000   Yes    IVL     No
        Port Members: 26,28,30,32,34,36,47-48
Total VLANs: 4

Let’s just check the Multi-Link Trunk configuration… if that’s wrong we could end up with a loop in the network;

4548GT-PWR(config)#show mlt 1
Id Name                 Members                Bpdu   Mode           Status
-- -------------------- ---------------------- ------ -------------- -------
1  MLT_to_ERS5520       47-48                  All    Basic          Enabled

You can see from the commands above that the ports are configured with the appropriate VLANs and the MLT is enabled.

Ethernet Routing Switch 5520

Let’s add the necessary configuration to the Ethernet Routing Switch 5520-PWR. I’m not going to repeat all the commands I performed in the yesterday’s post, instead I’ll just build upon the previous configuration adding what we need for the 802.1q trunking and the Multi-Link Trunking;

enable
config t
vlan port 47,48 tagging TagAll
vlan members add 1 47,48
vlan members add 100 47,48
vlan members add 200 47,48
vlan port 47,48 pvid 1

mlt 1 disable
mlt 1 name "MLT_to_ERS4548"
mlt 1 learning disable
mlt 1 member 47,48
mlt 1 enable

Ethernet Routing Switch 5520 – Show Configuration

That should be the configuration for the Ethernet Routing Switch 5520… let’s just have a quick look at the VLANs;

5520-48T-PWR#show vlan
Id  Name                 Type     Protocol         PID      Active IVL/SVL Mgmt
--- -------------------- -------- ---------------- -------- ------ ------- ----
1   test                 Port     None             0x0000   Yes    IVL     Yes
        Port Members: 1-12,37-48
100 192-168-100-0/24     Port     None             0x0000   Yes    IVL     No
        Port Members: 13-24,47-48
101 10-101-20-0/24       Port     None             0x0000   Yes    IVL     No
        Port Members: 25-36
200 192-168-200-0/24     Port     None             0x0000   Yes    IVL     No
        Port Members: 47-48
Total VLANs: 4

Let’s just check the Multi-Link Trunk configuration… if that’s wrong we could end up with a loop in the network;

5520-48T-PWR#show mlt 1
Id Name             Members                Bpdu   Mode           Status  Type
-- ---------------- ---------------------- ------ -------------- ------- ------
1  MLT_to_ERS4548   47-48                  All    Basic          Enabled Trunk

Since all stackable Avaya Ethernet Routing Switches support Auto-MDIX I can just use two regular CAT5e patch cables to connect the switches together. If the switches didn’t support Auto-MDIX I would need to use two crossover cables between them.

Ethernet Routing Switch 4548 – Operational Status

With link up on ports 47 and 48 I can check the following information. The topology table will show me the physical connections between the two switches. The MAC/FDB table will show me that there are multiple MAC/FDB entries in VLANs 100 and 200 being learned across “Trunk 1″. The LLDP table will show me the Avaya IP phones that I’ve connected to ports 25 and 26.

4548GT-PWR#show autotopology nmm-table
LSlot                                                                     RSlot
LPort IP Addr          Seg ID  MAC Addr     Chassis Type     BT LS   CS   RPort
----- --------------- -------- ------------ ---------------- -- --- ----  -----
0/ 0 192.168.1.25    0x000000 001E7E7C2C01 4548GT-PWR       12 Yes HTBT    NA
1/47 192.168.1.50    0x000130 001F0ACEBC01 5520-48T-PWR     12 Yes HTBT   1/48
1/48 192.168.1.50    0x00012f 001F0ACEBC01 5520-48T-PWR     12 Yes HTBT   1/47

4548GT-PWR#show mac-address-table
Mac Address Table Aging Time: 300
Number of addresses: 20

   MAC Address    Vid  Source         MAC Address    Vid  Source
----------------- ---- -------     ----------------- ---- -------
00-02-B3-CB-77-A2    1 Port:19     00-04-61-9E-46-7E    1 Port:21
00-0C-29-64-33-F9    1 Port:19     00-0C-29-A5-CB-54    1 Port:19
00-18-01-EA-F4-45    1 Port: 1     00-1C-11-6B-DC-6B    1 Port: 1
00-1C-11-6D-15-27    1 Port: 1     00-1C-11-6D-15-DC    1 Port: 1
00-1E-7E-7C-2C-00    1             00-1E-7E-7C-2C-40    1
00-1F-0A-CE-BC-40    1 Trunk:1     00-1F-D0-D0-BE-2D    1 Port:17
00-23-EE-96-AA-21    1 Port: 1     00-24-B5-F6-94-02    1 Trunk:1
00-0A-E4-76-9C-C8    2 Port:45     00-1F-0A-CE-BC-01    2 Trunk:1
00-24-DC-DF-0D-08    2 Port:43     00-A0-F8-5E-CE-BC    2 Port:39
00-1F-0A-CE-BC-41  100 Trunk:1     00-24-7F-99-84-70  100 Port:25
00-24-7F-99-84-E9  100 Trunk:1     00-1E-CA-F3-1D-B4  200 Port:26

4548GT-PWR#show lldp neighbor
-------------------------------------------------------------------------------
                            lldp neighbor
-------------------------------------------------------------------------------
Port: 26    Index: 4                  Time: 13 days, 22:42:31
        ChassisId: Network address    IPv4  192.168.200.5
        PortId:    MAC address        00:1e:ca:f3:1d:b4
        SysCap:    TB / TB            (Supported/Enabled)
        PortDesc:  Avaya IP Phone
        SysDescr:  Avaya IP Telephone 1120E, Firmware:SIP1120e04.00.04.00

-------------------------------------------------------------------------------
Port: 25    Index: 6                  Time: 13 days, 22:43:48
        ChassisId: Network address    IPv4  192.168.100.98
        PortId:    MAC address        00:24:7f:99:84:70
        SysCap:    TB / TB            (Supported/Enabled)
        PortDesc:  Avaya IP Phone
        SysDescr:  Avaya IP Telephone 1220, Firmware:SIP12x004.00.04.00

-------------------------------------------------------------------------------
Sys capability: O-Other; R-Repeater; B-Bridge; W-WLAN accesspoint; r-Router;
T-Telephone; D-DOCSIS cable device; S-Station only.
Total neighbors: 2

Ethernet Routing Switch 5520 – Operational Status

I can check all the same information on the ERS5520.. The topology table will show me the physical connections between the two switches. The MAC/FDB table will show me that there are multiple MAC/FDB entries in VLANs 100 and 200 being learned across “Trunk 1″. The LLDP table will show me the Avaya IP phones that I’ve connected to ports 13 and 25.

5520-48T-PWR#show autotopology nmm-table
LSlot                                                                     RSlot
LPort IP Addr          Seg ID  MAC Addr     Chassis Type     BT LS   CS   RPort
----- --------------- -------- ------------ ---------------- -- --- ----  -----
 0/ 0 192.168.1.50    0x000000 001F0ACEBC01 5520-48T-PWR     12 Yes TPCH    NA
 1/47 192.168.1.25    0x00012f 001E7E7C2C01 4548GT-PWR       12 Yes TPCH   1/47
 1/48 192.168.1.25    0x000130 001E7E7C2C01 4548GT-PWR       12 Yes TPCH   1/48

5520-48T-PWR#show mac-address-table
Mac Address Table Aging Time: 300
Number of addresses: 16

   MAC Address    Vid  Source         MAC Address    Vid  Source
----------------- ---- -------     ----------------- ---- -------
00-02-B3-CB-77-A2    1 Trunk:1     00-04-61-9E-46-7E    1 Trunk:1
00-0C-29-64-33-F9    1 Trunk:1     00-0C-29-A5-CB-54    1 Trunk:1
00-18-01-EA-F4-45    1 Trunk:1     00-1C-11-6B-DC-6B    1 Trunk:1
00-1C-11-6D-15-27    1 Trunk:1     00-1C-11-6D-15-DC    1 Trunk:1
00-1E-7E-7C-2C-01    1 Trunk:1     00-1E-7E-7C-2C-40    1 Trunk:1
00-1F-0A-CE-BC-00    1             00-1F-0A-CE-BC-40    1
00-1F-D0-D0-BE-2D    1 Trunk:1     00-23-EE-96-AA-21    1 Trunk:1
00-24-B5-F6-94-02    1 Port: 9     00-1F-0A-CE-BC-41  100
00-24-7F-99-84-70  100 Trunk:1     00-24-7F-99-84-E9  100 Port:15
00-1E-CA-F3-1D-B4  200 Trunk:1

5520-48T-PWR#show lldp neighbor
-------------------------------------------------------------------------------
                            lldp neighbor
-------------------------------------------------------------------------------
Port: 13     Index: 5                  Time: 0 days, 00:02:00
        ChassisId: Network address    IPv4  192.168.100.4
        PortId:    MAC address        00:24:b5:f6:94:02
        SysCap:    TB / TB            (Supported/Enabled)
        PortDesc:  Avaya IP Phone
        SysDescr:  Avaya IP Telephone 1165E, Firmware:SIP1165e04.00.04.00

-------------------------------------------------------------------------------
Port: 25    Index: 6                  Time: 0 days, 00:02:19
        ChassisId: Network address    IPv4  192.168.200.99
        PortId:    MAC address        00:24:7f:99:84:e9
        SysCap:    TB / TB            (Supported/Enabled)
        PortDesc:  Avaya IP Phone
        SysDescr:  Avaya IP Telephone 1220, Firmware:SIP12x004.00.04.00

-------------------------------------------------------------------------------
Sys capability: O-Other; R-Repeater; B-Bridge; W-WLAN accesspoint; r-Router;
T-Telephone; D-DOCSIS cable device; S-Station only.
Total neighbors: 2

Would you be interested in seeing a screencast of this whole process?

Let me know if you have any questions or would like to point out corrections!

Cheers!

Nortel Internet Telephones – Network Loops

0
May 6, 2008
by Michael McNamara in

j0401818 A Tek-Tips forum member recently reported that one of his technicians improperly cabled a Nortel i2002/i2004 Internet Telephone (plugging both the ports on the back of the Internet Telephone into the network switch) causing a loop which took down their entire network. The member was curious about how to configure Spanning Tree to help prevent this problem. I went digging and found the following information in the current phone firmware release notes;

Network Loop (Applies to IP Phone 2002, 2004, 2007, 1120E, 1140E)
These firmware releases include a fix to help prevent network loop scenarios from being introduced into the network, and the resultant network outages that can occur. The network loop avoidance fix was first introduced in 0604D9H, 0621C2B, 0624C1E and 0625C1E. One important note when upgrading to 0604DBN, 0621C4T, 0624C4L or 0625C4L from any load previous to 0604D9H, 0621C2B, 0624C1E or 0625C1E respectively, is that IP Phones that were inadvertently mis-wired during initial installation will not be allowed to work until the cabling problem is corrected. This fix is only an issue if the installer, when installing the Nortel IP Phone 2002, 2004, 2007, 1120E or 1140E, inadvertently connected the network Ethernet cable to the PC Ethernet port on the back of the phone, instead of connecting it to the network Ethernet port on the back of the phone. Phase II IP Phones (2002 and 2004) running firmware previous to 0604D9H, IP Phones 2007 running firmware previous to 0621C2B and IP Phone 1120E and 1140E running firmware previous to 0624C1C and 0625C1C respectively will work when incorrectly connected, but this does introduce the potential for network degradation. These new firmware loads will try and safe guard the network by trying to prevent phones that are mis-cabled to function. This means that the IP Phones that are working on a previous release of firmware may stop working if they are not correctly wired.

But realize that a mis-cabled phone may still work, even with the new firmware, if the network infrastructure supports Auto MDIX. If the network infrastructure supports Auto MDIX, network loop can still occur if the network is not running the Spanning Tree Protocol (STP) or a similar loop avoidance protocol.

As a preventative measure to reduce the potential for network degradation, and to prevent mis-cabled phones from ceasing to work when their firmware is upgraded, please consider taking the necessary steps to ensure your Nortel IP phones network cables are plugged into the correct ports on the back of the phone – network cable into the network Ethernet port, and the PC Ethernet cable (if connecting a PC) to the PC Ethernet port (little computer icon) on the back of the phone.

I’ve highlight a very important caveat above in RED. While this was and is a great feature of the new phone firmware the important piece to realize here is that if the network switch supports Auto MDIX, which the Nortel Ethernet Routing Switch 5520 and Ethernet Switch 470 PWR do you can’t rely on this feature alone to protect your network.

Ever since the release of the Nortel Ethernet Switch 470 we now configure Spanning Tree on every port with the exception of the core MLT/SMLT uplinks. Prior to the availability of the “Auto MDIX” feature a technician would need a crossover cable to physically put a loop between two switch ports. We made sure there were never any crossover cables left lying around. With the arrival of the “Auto MDIX” feature technicians could now put a loop in the switch with a standard straight-thru cable, which happened on a number of occasions. In order to prevent this problem we reconfigured every closet to run Spanning Tree locally on that switch. We would not run it on the uplinks but we would run it on all other ports in the switch/stack.

Here are some of the commands to enable Spanning Tree with Fast Learning on ports 1-46 of an ERS 5520 switch;

5520-48T-PWR> enable
5520-48T-PWR# configure terminal
5520-48T-PWR (config)# interface fastEthernet 1-46
5520-48T-PWR (config-if)# spanning-tree learning fast
5520-48T-PWR (config-if)# exit
5520-48T-PWR (config)#

Cheers!

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