Trunking Catalyst 2950 to Catalyst 3750 problem

I cannot seem to figure out how to trunk a catalyst 3750 to a Catalyst 2950.
I've set
3750(config)#interface fastethernet 1/0/2
switchport mode trunk
switchport trunk encapsulation dot1q
BUT my Catalyst 2950 does not offer the "switchport trunk encapsulation dot1q" command
My 2950 is running IOS version 12.1(20)EA1a
is there a work around for this situation. Our network still employs a bunch of these 2950's.

The Catalyst 2950 series can only do 802.1Q trunking. It's the default, and only, choice. So there's no need to specify it when trunking.
In fact, since you don't have a choice of which encapsulation to use, there's no need for a "switchport trunk encapsulation" command. Which is why it's missing from the Cat2950 switch IOS.
This took me by surprise too, when I first transitioned out of the 3500XL series into 2950 and 3550 switches.

Similar Messages

Catalyst (3750 24 10/100/1000T) and (3750 12 SFP) Stacking Problems

Dear all
I'm having a very strange situation here (at least for me)
we have 4 core switches
2 x   WS-C3750G-24T-S Catalyst 3750 24 10/100/1000T + IPB Image
and
2 x   WS-C3750G-12S-S Catalyst 3750 12 SFP + IPB Image
Stack configuration is done this way
when the switches are powered on, the first two SFP core switches are seen as a single stack with the stack master LED turned green on the first switch
the other two (24 10/100/1000T) switches have the RPS LEDs always green, mode cannot be changed, and cannot be accessed by Console connection
but when the (24 10/100/1000T) are powered off, the first (SFP) switch in the stack reports that " Switch 3 and 4 has been removed from Stack "
which means they are stacked but there's something wrong, because
only the SFP ports are shown in the " Show interfaces status " , the ethernet ports of the bottom switches are not present !!!
can you please tell me what's the poblem ?

Dear Daniel
Sorry for my delayed response but i was actually quite busy
but the problem was actually in another sense
the default profile for the Catalyst 3750 SFP is the Aggregate SDM Template
while the 3750 10/100/1000 ethernet Switch Default SDM profile was Desktop profile
so i had an SDM mismatch
DATACENTER#sh switch detail
Switch/Stack Mac Address : 081f.f3cf.1c80
                                           H/W   Current
Switch# Role   Mac Address     Priority Version State
*1       Master 081f.f3cf.1c80     1      0       Ready
2       Member 081f.f3cf.5900     1      0       Ready
3       Member aca0.16ac.0180     1      2       SDM Mismatch
4       Member aca0.16a3.bc80     1      2       SDM Mismatch
         Stack Port Status             Neighbors
Switch# Port 1     Port 2           Port 1   Port 2
1        Ok         Ok                2        4
2        Ok         Ok                3        1
3        Ok         Ok                4        2
4        Ok         Ok                1        3
all i did was changing the default profile of the SFP switches into the Desktop Profile and problem was solved
switch 1 provision ws-c3750g-12s
switch 2 provision ws-c3750g-12s
switch 3 provision ws-c3750g-24t
switch 4 provision ws-c3750g-24t
system mtu routing 1500
ip subnet-zero
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
vlan internal allocation policy ascending
interface GigabitEthernet1/0/1
interface GigabitEthernet1/0/2
interface GigabitEthernet1/0/3
interface GigabitEthernet1/0/4
interface GigabitEthernet1/0/5
interface GigabitEthernet1/0/6
interface GigabitEthernet1/0/7
interface GigabitEthernet1/0/8
interface GigabitEthernet1/0/9
interface GigabitEthernet1/0/10
interface GigabitEthernet1/0/11
interface GigabitEthernet1/0/12
interface GigabitEthernet2/0/1
interface GigabitEthernet2/0/2
interface GigabitEthernet2/0/3
switchport trunk encapsulation dot1q
switchport mode trunk
interface GigabitEthernet2/0/4
interface GigabitEthernet2/0/5
interface GigabitEthernet2/0/6
interface GigabitEthernet2/0/7
interface GigabitEthernet2/0/8
interface GigabitEthernet2/0/9
interface GigabitEthernet2/0/10
interface GigabitEthernet2/0/11
interface GigabitEthernet2/0/12
interface GigabitEthernet3/0/1
interface GigabitEthernet3/0/2
interface GigabitEthernet3/0/3
interface GigabitEthernet3/0/4
interface GigabitEthernet3/0/5
interface GigabitEthernet3/0/6
interface GigabitEthernet3/0/7
interface GigabitEthernet3/0/8
interface GigabitEthernet3/0/9
interface GigabitEthernet3/0/10
interface GigabitEthernet3/0/11
interface GigabitEthernet3/0/12
interface GigabitEthernet3/0/13
interface GigabitEthernet3/0/14
interface GigabitEthernet3/0/15
interface GigabitEthernet3/0/16
interface GigabitEthernet3/0/17
interface GigabitEthernet3/0/18
interface GigabitEthernet3/0/19
interface GigabitEthernet3/0/20
interface GigabitEthernet3/0/21
interface GigabitEthernet3/0/22
interface GigabitEthernet3/0/23
interface GigabitEthernet3/0/24
interface GigabitEthernet4/0/1
interface GigabitEthernet4/0/2
interface GigabitEthernet4/0/3
interface GigabitEthernet4/0/4
interface GigabitEthernet4/0/5
interface GigabitEthernet4/0/6
interface GigabitEthernet4/0/7
interface GigabitEthernet4/0/8
interface GigabitEthernet4/0/9
interface GigabitEthernet4/0/10
interface GigabitEthernet4/0/11
interface GigabitEthernet4/0/12
interface GigabitEthernet4/0/13
interface GigabitEthernet4/0/14
interface GigabitEthernet4/0/15
interface GigabitEthernet4/0/16
interface GigabitEthernet4/0/17
interface GigabitEthernet4/0/18
interface GigabitEthernet4/0/19
interface GigabitEthernet4/0/20
interface GigabitEthernet4/0/21
interface GigabitEthernet4/0/22
interface GigabitEthernet4/0/23
interface GigabitEthernet4/0/24
that's it !
: D
cheers

VLAN trunking from Cisco Catalyst 3750 to Cisco SF300-48P issue and related

Hello expert,
I'm having difficulties to configure VLAN trunking between Cisco Catalyst 3750 switch with Cisco SF300-48P switch and my workstation unable to get any DHCP IP from our DHCP server via Cisco SF300-48P switch. Below is the snippet of configuration on both switches:
[Cisco Catalyst 3750 Switch]
interface GigabitEthernet1/0/45
description NCC-CC-1stFlr
no switchport trunk encapsulation dot1q
no switchport trunk allowed vlan 101-103
spanning-tree portfast
[Cisco SF300-48P Switch]
interface fastethernet48
spanning-tree link-type point-to-point
switchport trunk allowed vlan add 101-103
macro description switch
!next command is internal.
macro auto smartport dynamic_type switch
interface fastethernet29
switchport mode general
switchport general allowed vlan add 103 tagged
switchport general pvid 103
Are these are correct? Kindly advice!
Thank you very much!
Regards,
Alex

Hi Alex,
for the trunk port on Catalyst on port GE 1/0/45, we need to enable the trunk and for on encapsulation dot1q because this catalyst model is ISL capable also and the SF300 working only with Dot1q Encapsultion
The configuration on catalyst should :
#config terminal
#interface Gi 1/0/45
# switchport encapsulation
#switchport trunk encapsulation dot1q
#switchport mode trunk
#switchport trunk allowed vlan 101-103
#spanning-tree portfast
For SF300 the port trunk it looks fine but for the port where the PC should receive an IP address
#interface fastethernet29
#switchport mode access
#switchport ccess vlan 103
Please let me know after this configuration
Thanks
Mehdi
Please rate or mark as answered to help other Cisco Customers

Trunking between Huawei S3900 and Cisco catalyst 3750

One of my edge Huawei S3700 switches is dead, I am going to replace it with a Cisco switch Catalyst 3750 series PoE-48 via a trunk link with GE fiber port on both ends, please see the diagram below.
trunk trunk
Core switchrouter<----------S3700<--------------->Cisco Catlyst 3750
I haven’t touch Cisco switch for many years, I would like to ask the following questions:
1.)      Do I need to take any precaution before connecting this Cisco switch into my Huawei network? Only one link between S3700 and C3750, so I don't need worry anout STP? Do I need to worry about Default vlan regarding trunking port?
2.)      I need to use different trucking protocol e.g. 802.1Q etc to interconnect these two switches (S3700-28TP-SI-AC and Catalyst 3750), please see the following configuration:
For C3750:
switchport trunk encapsulation dot1q
switchport trunk native vlan (What you want)
switchport trunk allowed vlan (VLANs required)
switchport mode trunk
spanning-tree portfast trunk
For S3700:
port link-type trunk
port trunk permit vlan all
Do you think the configurations above are right?
Do I need to manually enter Duplex and speed options ?
3.)If the configurations are not right, then what are the commands for trucking port/link should I use on the Cisco switch (it uses IOS software) and Huawei switch? Procedures of the commands would be really helpful !
Any information and help would be much appreciated.
Thanks
Regards

Hello
3750 - basic config
================
See as you are using this switch as an host switch you need to make sure ip routing isn't enabled ( it isn't by default)
Also it looks like the s3700 Huawei switch is permitting all vlans and I assuming the default native vlan is 1 ( as is cisco) so no need to specify the native either.
If you are requiring the access ports on this new cisco 3750 to be in multiple vlans then usually cisco to cisco interconnect would ultise VTP for vlan propagation however this wont occur between the Huawei switch, so you will need to manually add the vlans on the switch also.
so to summarize below is a basic host switch config for 3750.
conf t
no ip routing
hostname XXXXXX
username xxxx privilege 15 secret xxxxxxx
service password-encryption
enable secret xxxxx
security passwords min-length xx
security authentication failure rate xx log
aaa new-model aaa authentication login default local
logging buffered 4096
no service udp-small-servers
no service tcp-small-servers
service timestamps debug datetime msec localtime
service timestamps log datetime msec localtime
no ip domain-lookup
spanning-tree mode rapid-pvst
spanning-tree portfast bpduguard default
int vlan x ( this may or not be vlan 1 - its whatever the L3 vlan interface is on the core switch for management connectivity)
ip address x.x.x.x y.y.y.y.
exit
ip default-gateway x.x.x.x ( ip address of CORE SVI management interface)
vlan x,x,x,x ( add the L2 vlans to the switch as vtp would not be used between the Huawei switch)
exit
int gigx/x
Description Link to Huawei switch
switchport trunk encapsulation dot1q
switchport mode trunk
switchport nonegotiate
no shut
( no need for spanning-tree portfast trunk- this is usually only for ESX host ports)
int rang fa0/1 -48
Description - Access-ports
switchport host
switchport access vlan x (wihout this defaults to vlan 1)
no shut
clock timezone gmt 0
ntp peer
ntp server x.x.x. prefer
res
Paul

Password problem on Catalyst 3750

Hi all,
I am an Unix administrator and we lost all account and password informations to connect on a Catalyst 3750 switch.
Is there a way to connect to the switch (With a serial cable?) an to create a new account without losing the configuration ?
Thank's for your reply.
Regards.

This method won't reset the configuration.
During the boot process, you rename the current configuration so it doesn't get loaded.
rename flash:config.text flash:config.old
When the switch boots, it loads a blank image. Then you rename the config file and load it into the running config and you can change the logon credentials to something you know.
It's important that you follow the steps exactly so you don't lose the configuration. Password recovery is a pretty common procedure.
The only other method of recovery is if you have a copy of the current running configuration. Send me a private message if you have this config and we can discuss the possibility.

System FCS error frames on Catalyst 3750

Please,
may someone explain what are the "System FCS error frames" I see with "show controllers ethernet-controller" on some ports of a Catalyst (on trunk and also on access ports) WS-C3750G-24TS-S (3 switches in stackwyse)?
Error counters advance slowly, but they do grow... and I am afraid this could be the reason for variable slow access time to a server application menu...
For example "8 System FCS error frames".
The ports are connected to a PIX-515E and I see the same error count on the firewall interfaces (PIX "show interface" command shows me "8 input errors, 8 CRC, 0 frame, 0 overrun, 8 ignored, 0 abort")
A few errors may be seen also on other ports, connected to other (C3550)switches.
I tried to upgrade the IOS version, so I loaded "ipbase 12.2(25)SEB4 " on the Catalyst 3750, but it did not solve the problem.
PIX firewalls are running software 6.3(4).
Why these errors are called "System FCS error frames" ? I could not find anything searching on Cisco CCO!
Thanks

I apologies for the delay answering, my notebook has been down for 5 days and also cco access password...
Thank you for the explanation and suggestion.
We have a second rack with another three switch 4750 in stackwyse, same models as the "faulty" ones, and the errors are not present on those switches, so it must be something hardware related on the first group of switches.
I cannot touch those devices at the moment, we captured traffic frames with 3 Notebook PCs running "Ethereral" lan sniffer, traffic to and from the server and two clients and we discovered that in different ports of those switches, some packets never reach the clients, causing many TCP retransmissions, especially witch continuous traffic (http get and ftp transfers). This problem is visible on some, but not all, of the catalsyt 3750 switches in stackwyse, but in every one of the three switches. We are planning to go on-site and replace the hopefully faulty one ( or reseat the cables as you suggested).
Is this a problem you have seen before?
Regards
Franco Feri

Policer with IPv6 class-map on Catalyst 3750

Hi,
I've the following problem.
It's my goal to ratelimit incoming IPv6 traffic dependent on the destination IP address range.
On a Catalyst 3750 (Image: c3750-ipservicesk9-mz.122-55.SE1.bin) I've set up the configuration as follows:
mls qos
ipv6 access-list DESTINATION-RANGE-A
permit ipv6 any 2007::/16
ipv6 access-list DESTINATION-RANGE-B
permit ipv6 any 2B03::/16
class-map match-all A
match access-group name DESTINATION-RANGE-A
class-map match-all B
match access-group name DESTINATION-RANGE-B
policy-map RL-POLICY
class A
police 2000000 8000 exceed-action drop
class B
police 6000000 8000 exceed-action drop
interface GigabitEthernet1/0/7
switchport access vlan 90
load-interval 30
service-policy input RL-POLICY
The last CLI command which should bind the policy to the specific interface, leads to the following error message
QoS: class(A) IPv6 class not supported on interface GigabitEthernet1/0/7
Are hardware/software limitations the reason for this behavior or is there any misconfiguration?
Thanks in advance for your help!
Regards,
Jens

If you are thinking of IPv6 prefix I tried everything. From /128 for single host to /64, nothing works.

Ratelimiter with IPv6 class-map on Catalyst 3750

Hi,
I've the following problem.
It's my goal to ratelimit incoming IPv6 traffic dependent on the destination IP address range.
On a Catalyst 3750 (Image: c3750-ipservicesk9-mz.122-55.SE1.bin) I've set up the configuration as follows:
mls qos
ipv6 access-list DESTINATION-RANGE-A
permit ipv6 any 2007::/16
ipv6 access-list DESTINATION-RANGE-B
permit ipv6 any 2B03::/16
class-map match-all A
match access-group name DESTINATION-RANGE-A
class-map match-all B
match access-group name DESTINATION-RANGE-B
policy-map RL-POLICY
class A
police 2000000 8000 exceed-action drop
class B
police 6000000 8000 exceed-action drop
interface GigabitEthernet1/0/7
switchport access vlan 90
load-interval 30
service-policy input RL-POLICY
The last CLI command which should bind the policy to the specific interface, leads to the following error message
QoS: class(A) IPv6 class not supported on interface GigabitEthernet1/0/7
Are hardware/software limitations the reason for this behavior or is there any misconfiguration?
Thanks in advance for your help!
Regards,
Jens

If you are thinking of IPv6 prefix I tried everything. From /128 for single host to /64, nothing works.

Debian Linux Bonding and Cisco Catalyst 3750 - best practise?

Hello everybody,
I would like to know what's best practice to do this:
The two NICs of a Debian Linux server wants to be connected with two Switchports of a Cisco Catalyst 3750 switch(stack). My goal is to have load-balancing and failover.
My /etc/network/interfaces looks like this:
iface bond0 inet static
       address 192.168.0.30
       netmask 255.255.255.0
       network 192.168.0.0
       broadcast 192.168.0.255
       gateway 192.168.0.1
       dns-nameservers 192.168.0.10 192.168.0.20
       dns-search xyz.mycompany.com
       slaves eth0 eth1
       bond_mode ???
       bond_miimon 100
       bond_downdelay 200
       bond-updelay 200
First question: What bond mode should I use?
The switchports looks like this:
interface GigabitEthernet3/0/4
switchport access vlan 20
switchport mode access
spanning-tree portfast
What changes are necessery here? Something like this?
interface GigabitEthernet3/0/4
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree portfast
Thanks a lot for suggestions, hints, etc.! :-)
Greets
Stephan

Hi Michael,
thanks a lot for your answer - and sorry for my late reply!
I like to show you my solution - I hope that it is a solution. ;-)
My config on the switch(stack):
switch#show etherchannel summary
Group Port-channel Protocol    Ports
------+-------------+-----------+-----------------------------------------------
2      Po2(SU)         LACP      Gi3/0/3(P) Gi4/0/3(P)
switch#show running-config interface GigabitEthernet 3/0/3
Building configuration...
Current configuration : 172 bytes
interface GigabitEthernet3/0/3
description myserver, eth0
switchport access vlan 20
switchport mode access
channel-group 2 mode active
spanning-tree portfast
end
lansw01#show running-config interface GigabitEthernet 4/0/3
Building configuration...
Current configuration : 172 bytes
interface GigabitEthernet4/0/3
description myserver, eth1
switchport access vlan 20
switchport mode access
channel-group 2 mode active
spanning-tree portfast
end
switch#show running-config interface port-channel 2
Building configuration...
Current configuration : 82 bytes
interface Port-channel2
switchport access vlan 20
switchport mode access
end
The /etc/network/interfaces of my Debian machine looks like this:
auto lo
iface lo inet loopback
auto bond0
        iface bond0 inet static
        address 192.168.1.xxx
        netmask 255.255.255.0
        gateway 192.168.1.xxx
        dns-nameservers 192.168.1.xxx
        dns-search xxx.xxx.xxx
        bond-mode 4
        bond-miimon 100
        bond-downdelay 200
        bond-updelay 200
        bond-lacp-rate 1
        slaves eth0 eth1
This setup seems to work well. But I'm wondering that there is nothing with "trunking" in my setup. Would you like to give me your opinion about this?
Thanks a lot and many greets
Stephan

Interconnecting Catalyst 3750 and 2948G-L3

I am trying to interconnect a Catalyst 3750 and a 2948G-L3 using fiber GBIC. The interfaces where the GBIC and fiber are attached show up as physically down. I have tried different ports and also changed both switches. No Luck. If I connect a 3524 to the 3750 using the same connection it works.
Are 2948G-L3 switches compatible with the 3750?
Thanks,
VT

Should have no problem. Can you try the following on the 3750's gig interface:
speed nonegotiate
See of the link comes up.
Please rate all posts.

I cannot connect by console port to Cisco Catalyst 3750 using ethernet to USB.

Hello. I have one Cisco Catalyst 3750 switch, and two 2950 switches. I am trying to reset their settings using a console cable with a trendnet Ethernet to USB adapter. When I try loading hyperterm or putty on com3 there is no signal. I have the communication port setting on com3. I don't know what the old settings are, and they can be reset. I get connectivity lights when plugging the cable into the switch ports. What am I missing?

Are you definitely using the correct COM Port number? On Windows7 Right Click My Computer > Manage Then select Device Manager and expanPorts (COM & LPT)d in my case is shows Prolific USB-to-Serial Comm Port (COM5).
Once you have the right COM Port number just use the default settings in Putty. You may find the COM Port is locked up which will require a reboot.

Configuring dual-links on catalyst 3750

I've dual-links (laser and Fiber optic media) to connect my office and colocation. both of using catalyst 3750, there are also 4 VLAN. the problem are Fiber optic provider only allow 1 VLAN to connect my network to colocation, when the Laser drop, Fiber optic can't send traffic to colocation.
is there any clue for this problem...?
thanks,

Hey,
Please give the Show config output from both the switches. Would like to see the config on both the ends.
regards,
-amit singh

Do Cisco router 2811 and Catalyst 3750 support SNMPv3?

Hi,
Do Cisco router 2811, IOS 12.4(20)Ti, and Catalyst 3750, IOS 12.2.(53)SE, support SNMPv3?
Attached file contains my SNMPv3 configurations and "show snmp" results. Would you please give me your advice? Thanks.
Hugh

Hugh
Certainly both the 2811 and the 3750 do support SNMPv3. So support for the feature is not an issue in your situation.
I have looked at the config that you attached and believe that it looks reasonable. You have not told us about the SNMP server that will communicate with these devices. So we have no way to know if the details of the configuration are correct.
Have you attempted to discover these devices with an SNMP server that is configured to use SNMPv3 and has this user and passwords configured? If it does not work my first suggestion would be to check to verify that the passwords configured are exactly the same on the clients and on the server (and perhaps re-configure the passwords just to be sure). If the passwords are not a problem my second suggestion would be to check and verify that the authentication and encryption parameters match between the server and the clients.
HTH
Rick

Catalyst 3750 12.2(25)SD1 and dual nics

When a Catalyst 3750 stack master fails or leaves the stack, a cross-stack EtherChannel in trunk mode running Link Aggregation Control Protocol (LACP) protocol might stop forwarding traffic on some VLANs.
The workaround is to enable the stack-mac persistent feature by using the stack-mac persistent timer global configuration command. You can also use the shutdown interface configuration command and then the no shutdown command on the EtherChannel interface.
Network Infrastructure: LAN Routing and Switching
I have upgrade a Catalyst 37024 TS 2 switch stack to 12.2(25)SED1 from 12.1(14)EA. The switch has an Alpha Server Custer connected to it the cluster has two servers each having two nics . There is a active server which has an application IP address and each server has a Server IP address one nic active ata time.
All worked ok upto the upgrade. Now every night when the backup runs noone can access the application ip address or the acive server address but te offline server is pingable. This is only for devices outside the serrver VLAN. Devices within the server VLAN can hapily ping any address.
I thought this was arouing issue but all looks ok and the offline server can be pinged from any where.
the active server nics areon 1/0/20 and 2/0/24
Any one have any ideas?

I forgot to add if I shut both interfaces an then do a no shout on both the issue is resolved until the next night.

Mls qos on Catalyst 3750

I can't understand dropping algorithm used by WTD on Catalyst 3750.
Giving the following configuration:
Switch(config)# mls qos queue-set output 2 buffers 40 20 20 20
Switch(config)# mls qos queue-set output 2 threshold 2 40 60 100 200
1. What happens if buffer utilization for queue 2 is between drop-threshold1 and drop-threshold2? Are the packets dropped using a specific algorithm as in WRED?
2. What happens if buffer utilization for queue 2 is between drop-threshold2 and maximum threshold? Are the packets dropped using another algorithm?
3. Is it true that with buffer utilization above maximum threshold all packets are dropped?
Thanks
Stefano

Paresh,
thanks a lot for your suggestions!
Anyway I still have some doubt related to WTD thresholds. The sintax is the following:
mls qos queue-set output qset-id threshold queue-id drop-threshold1 drop-threshold2 reserved-threshold maximum-threshold
For drop-threshold1 and drop-threshold2 the range is 1 to 400 percent. For reserved-threshold the range is 1 to 100 percent.
By default, drop-threshold1 and drop-threshold2 for queues 1, 3, and 4 are set to 100
percent. Drop-threshold1 and drop-threshold2 for queue 2 are set to 50 percent. The reserved
thresholds for queues 1, 3, and 4 are set to 50 percent. The reserved
threshold for queue 2 is set to 100 percent. The maximum thresholds for
all queues are set to 400 percent.
With these default settings, queue 2 has drop-threshold1 and drop-threshold2 set to 50 percent and reserved threshold set to 100 percent.
The problem is that drop-thresolds are percentage values related to the ENTIRE buffer, reserved threshold is related to the specific queue's buffer.
So with default settings (1/4 of total buffer for each queue) reserved threshold seems to be HIGHER than drop-thresolds!!!
reserved threshold = 1/4 total buffer
drop thresholds = 50% over 400% total buffer = 1/8 total buffer
Maybe there's something missing...
Thanks
Stefano

Trunking Catalyst 2950 to Catalyst 3750 problem

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