Dual-homed FEX

Looking for some guidance with a problem. I have 3 Nexus 2248T switches dual homed to 2 Nexus 5672 in the core. (See Attachment)
Problem: on one of the FEX I have an Exchange NLB cluster. Several of our systems that require POP3 mail to communicate messaging have experience connectivity issues (unable to send mail) and require the connection to be hard coded to one of the IP Address in a cluster server instead of the NLB address.
Configuration: I have not setup Spanning-tree on the trunk ports from the 5672s and am showing that BPDU guard is disabled for the edge ports.
Nexus5672-1# sh spanning-tree summary totals
Switch is in rapid-pvst mode
Root bridge for: none
Port Type Default is disable
Edge Port [PortFast] BPDU Guard Default is disabled
Edge Port [PortFast] BPDU Filter Default is disabled
Bridge Assurance is enabled
Loopguard Default is disabled
Pathcost method used is short
STP-Lite is enabled
Question: I am thinking I missed the "boat" on the configuration and need to include spanning-tree at the port level to correct the problem. Any advice please?

You don't need spanning tree config at the FEX level. You just need spanning tree on the 5762 devices to determine what device is the root and what device is the backup root.
HTH

Similar Messages

Single Homed or Dual Homed FEX

With the ability to do enhanced VPCs now on the FEXs is there any benefit to have a mixture of having of single attached FEXs and dual homed FEXs?
Here are some benefits as I see them
Single homed FEX is easier to trouble shoot as the topology is not as complex.
A dual homed FEX will support both dual attached hosts and a single attached host. So this means we only have one topology to deal with (everything dual homed)
Any other pros or cons?
Thanks

If you have any servers with only one uplink, you want dual homed FEXes for redundancy.
Also, it depend on the number of FEXes you are connecting to the same set of switches. For example: the max number of FEXes that can be uplinked to a set of 6k switches is 24 if you are dual homed, but if you are single homed the max is 48 (24 per switch).
HTH

Dual homed FEX configuration

Hi,
Have a question on dual homes FEX's
I have a FEX that's dual homed to 02 Nexus 5K'S
Lets say my FEX is 150 and if I want to configure port 150/1/1 to vlan 100, do I need to login to both Nexus 5K's and configure the port 150/1/1 to vlan 100?
OR Can config sync help
Thanks
stan

This is the wrong forum for this topic, but I'll assist.
Without configuration sync enabled, you would have to configure both Nexus 5K exactly the same for the FEX port before traffic will forward.
Configuration sync would help you in only having to configure it once, but I have had mixed results using configuration sync so I tend not to use it in my deployments.

Nexus 5548 SPAN Destination- Dual Homed FEX

I understand that order to setup a SPAN monitor session, only 5K local ports can be destination ports. Our FEX are dual homed, so I know we have to have the monitor session configured on both 5K's. We are wanting to connect an Infinistream sniffer to the destination port. What I am confused about is do we also have to have 2 destination ports, one on each 5K connecting to the Infinsitream or can we just use one?

You cannot set more than one destination to a monitor session. You can have multiple source interfaces, but only one destination. Try this:
destination interface e2/14
You will need to create two more separate monitoring session with the same source interfaces but set the destination to the other two interfaces.
HQ-N5k-2(config-if-range)# monitor session 1
HQ-N5k-2(config-monitor)# source interface e1/17 both
HQ-N5k-2(config-monitor)# destination interface e2/14
HQ-N5k-2(config-if-range)# monitor session 2
HQ-N5k-2(config-monitor)# source interface e1/17 both
HQ-N5k-2(config-monitor)# destination interface e2/15
HQ-N5k-2(config-if-range)# monitor session 3
HQ-N5k-2(config-monitor)# source interface e1/17 both
HQ-N5k-2(config-monitor)# destination interface e2/16
Please rate if helpful

How to replace Nexus5596 with dual-homing N2K

What is the correct process to replace a FEX parent switch with dual-homing fex?
Traffic should not be interrupted.

Hi
Do you have VPC between Parent Switches & are you running VPC on dual homed FEX fabric ports. ?
If yes Below is the procedure,
1) boot the replacement switch without VPC, peer-links & FEX ports connected to it.
2) Make sure it has same Software version matches with the peer switch.
3) enable Pre-Provisioning for slots with appropriate FEX model.
, here find the guide:
http://www.cisco.com/en/US/partner/docs/switches/datacenter/nexus5000/sw/system_management/521_n1_1/b_5k_System_Mgmt_Config_521N11_chapter_0100.html#task_05BB53AD7AFB49CF9A8E4A5C6C37CB38
So, on the replacement switch you will pre-provision the Fabric Extender and configure the ports so it will be ready when you add the module to the RMA SW.
Please make sure you put the appropriate FEX model on the provision slot, otherwise, when connected it will not come Online
Example, FEX 110:
N5K(config)# slot 110
N5K(config-slot)#provision model N2K-C2248T
4) Now keep all ports at Shut down state Then Configure Entire switch that includes FEX host ports, FEX Fabric Ports & VPC peer-link, VPC Domain Configuration.
keep FEX host ports in shut state.
5) keep VPC Role priority on existing switch lower than , new switch
6) Connect Peer-link ports to Peer switch & wait till VPC Comes up-
7) Then connect Fabric ports from FEX to the pre-configured ports on replacement switch
After it comes online Unshut FEX host ports.
I got similar steps here as well
http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/operations/n5k_vpc_ops.html#wp425197
NOTE: I followed same process however, few ping drops were seen....arnd ( 5- 6 ping loss) only on few hosts...
Mazhar

N5K - N2K Image Upgrade Single vs Dual Homed

Hi,
The upgrade distuptive behaviour is not explained well in the following documentation link . Especially about single homed FEX topology.
http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/upgrade/503_N1_1/n5k_upgrade_downgrade_503.html
1. I have just upgraded a dual homed Active / Active N2K to N5K environment as below. The downtime was exactly explained as above URL, just the time to reload the FEXs. Which was about 1.5 minutes or so...
Or should we NOT reload all the FEXs almost simultaneously by manual command (as mentioned in the upgrade guide) in this topology, in order to minimize the downtime ?
2.However I am curious if there would be any downtime in a single homed FEX topology as below. My guess is there would be just the downtime for the edge server to distribute the traffic to the other N2K.
I guess if the downtime is really a biggy, then the second topology is easier to manage.
Comments area very much appreciated.
Dumlu

I am not able to see the images you attached, could you please try reinserting them?
Also if I am understanding your question correctly, you are wanting to know if there will be downtime, if you upgrade a N5K with a 2K single homed. I assume you meaning something similar to this?
If so, yes the single home fex would be reloaded per the document it states: "Upgrade the first vPC switch (vPC primary switch) - during this upgrade, the switch will be reloaded. When the switch is reloaded, any dual-homed FEX will not be reloaded. Only singled-homed FEXs are reloaded. Servers connected to these dual-homed FEXs retain network connectivity via the second (vPC secondary) switch"

Dual homes FEX's N5K upgarde to 6.0 version

Hi,
I am planning ot have upgrades for N5K's which have dual homed FEX's and some catalyst switches connections to N5K's using vpc's and spanning tree port type network topology.
Now I have feq small queries.
1]Does ISSU pre-upgarde commands cuase nay discruption in services ?
eg :
sh install all impact
show incompatibility command
2] If Fex's are dual homed and could support ISSU, but due to some topology issues N5K's could not support ISSU, what could be best way to upgrade.
Regards
Ajay

One thing to keep in mind if you use multiple computers. Songs purchased with iTunes 6 can't be used by iTunes 4. So if you upgrade one machine to iTunes 6 you should upgrade all your computers to iTunes 6. Atleast if you want to share music between them.
Other than that there have been some changes to iTunes 6, but I can't remember off hand what functionality was in iTunes 4.7.1 as compared to the latest version. Maybe Apple has a version checklist somewhere on their site.
I'm sure some others will chime in with more answers but I see no reason why you shouldn't upgrade to iTunes 6.

Nexus 2K FEX dual-homed to two Nexus 5K Configuration

Hi.
I am trying to look for Nexus 5K config when the nexus2K FEX is dual-homed into it.
What will be the configuration on both 5K especiall the pinning?
Assuming one N2K 10G port is connected to N5K-1 and another N2K 10G port connected to N5K-2?
N5Ks are also configured as dual-sided vpc with two N7K.
thanks

N5k-1 ====vpc peer==== N5k-2
\ E1/10 E1/10 /
\ Fex-100 /
N5k-1 & N5k-2 config:
===============
Interface po100
switchport mode fex-fabric
fex associat 100
vpc 100
int e1/10
switchport mode fex-fabric
channel-group 100

Reducing the fex time for N2K dual homed to N5K

Hi,
We have N2K dual homed to 2 N5K. The N2K registers the fex with one of the N5K. But when one of the N5K fails it takes more than a minute to register with the second N5K.
How can we reduce this delay so that there is minimum timeout between failover ?

Hi David,
I just noticed that the VPC is DOWN, I think this is the root problem. Any suggestions on this ?
DC-ACC-2# show vpc
Legend:
                (*) - local vPC is down, forwarding via vPC peer-link
vPC domain id                   : 5
Peer status                     : peer link is down
vPC keep-alive status           : Suspended (Destination IP not reachable)
Configuration consistency status: failed
Per-vlan consistency status     : success
Configuration consistency reason: Consistency Check Not Performed
Type-2 consistency status       : success
vPC role                        : none established
Number of vPCs configured       : 1
Peer Gateway                    : Disabled
Dual-active excluded VLANs      : -
Graceful Consistency Check      : Disabled (due to peer configuration)
vPC Peer-link status
id   Port   Status Active vlans
1    Po5    down   -
vPC status
id     Port        Status Consistency Reason                     Active vlans
5      Po1         down   failed      Consistency Check Not      -
                                      Performed

Startup network configuration dual homed

FRUSTRATION: 100% .. Over a month trying to startup network configuration dual homed .. MacMini Intel Dual .. System Preferences --> Network --> Two Locations (BuiltIn ether on the IP my router uses for the world www, smtp, dns, ntp, limited ssh 192.168.local.wired.fixed) and (AirPort for VNC, ssh for admin via laptop)
Upon reboot, I have o login back to the Mini keyboard/CRT to reset these two locations. I am NOT passthru routing.
Bad enough the CRT settings will ot start my 20in VGA till I restart the video on an old low-res monitor.
No where near ready to install the Server pack. Looking thru the web stuff, there are Unix like files (missing) to force the addresses and default route. No ifconfigd found.
Where do I find a netconfig, rc.conf or like files to force the Mini (OS 10.4.7) to come up with my two interfaces and default route?
PLEASE .. Ev +1 805 340-6471 [email protected]

This is the wrong forum for this topic, but I'll assist.
Without configuration sync enabled, you would have to configure both Nexus 5K exactly the same for the FEX port before traffic will forward.
Configuration sync would help you in only having to configure it once, but I have had mixed results using configuration sync so I tend not to use it in my deployments.

Fabric Extender question to a dual-homed N5k

According to latest release notes:
http://www.cisco.com/en/US/customer/docs/switches/datacenter/nexus5000/sw/release/notes/Rel_4_2_1_N1_1/Nexus5000_Release_Notes_4_2_1_N1_1.html#wp144071
"Support for a maximum of 12 Fabric Extenders dual-homed to a vPC Cisco Nexus 5000 Series switch pair and a maximum of 576 hosts connected to Fabric Extenders connected to Cisco Nexus 5000 Series switches"
I have mixed mode so some of the FEX will only connect to one N5k despite the 2N5k will be vpc. Cisco calls this "Fabric extender straight-through topology". This is because I am running port-channel with VM on these particular FEX.
http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/C07-572829-00_Design_N5K_N2K_vPC_DG.pdf
question is:
1. Can I assume 2148 is included per release notes?
2. Can I have more than 2 ports in the portchannels in straight-through mode?
3. Release notes show 576 host which is (12 max times 48 ports). I assume I can have more logical host meaning vm host via the port channels, right...?
Thx

Any Nexus 5000 can have a total of 12 FEX's connected to it physically. If you have 12 FEX's in dual-homed mode, then that is the limit for both Nexus 5000's. If you had 24 FEX's evenly distributed between the Nexus 5000's in straight-through mode, then that would be maximum in that configuration. If you are mixing straight-through and dual-homed configurations, you would have to be within the 12 FEX per Nexus 5000 limit.
The 2148 is the first FEX, so yes it is the focus of the release notes.
The 2148 cannot have a local port-channel. This is why you can only channel to a 2148 when using dual-homed (called Active-Active mode), one interface on each 2148, and it is tied together with a vPC configuration to make a port-channel. The individual 2148's each only have one connection on them down to the server below. The 2248 and 2232 do not have this restriction.
As of 4.2(1)N1(1), 576 refers to host interfaces. If your host has virtual hosts, you just need to make sure you are within the limit of mac addresses in the system, which is 16,000 (13,800 unicast).
Regards,
John Gill
Reference:
configuration limits -
http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/configuration_limits/limits_421/config_limits_4_2_1_chapter1.html

Question re. behaviour of single homed FEX with vPC

Hi Folks,
I have been looking at configuring Nexus 5Ks with FEX modules. Referring to the Cisco documentation;
http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/layer2/513_n1_1/b_Cisco_n5k_layer2_config_gd_rel_513_N1_1_chapter_01001.html
In figure 3. showing a single homed FEX with vPC topology, I'm curious what happens if one of the 5Ks fail. For example if the 5K on the left hand side of the diagram fails do the ports on the attached FEX that the server is attached to drop? If not I would assume that the server has no way of knowing that there is no longer a valid path through those links and will continue to use them?
Many thanks in advance,
Shane.

Hello Shane.
Depending of type of the failureboth n5k can tace corrective actions and end host will always know that one of the port-channel members is down.
For example if one 5k will crash or will be reloaded - all connected fexes alre will go offline. FEX are not standalone switches and cannot work without "master" switch.
Also links which will go from fex to the end-host will be in vpc mode which means that all vpc redundancy features/advantages will be present.
HTH,
Alex

BGP in Dual Homing setup not failing over correctly

Hi all,
we have dual homed BGP connections to our sister company network but the failover testing is failing.
If i shutdown the WAN interface on the primary router, after about 5 minutes, everything converges and fails over fine.
But, if i shut the LAN interface down on the primary router, we never regain connectivity to the sister network.
Our two ASR's have an iBGP relationship and I can see that after a certain amount of time, the BGP routes with a next hop of the primary router get flushed from BGP and the prefferred exit path is through the secondary router. This bit works OK, but i believe that the return traffic is still attempting to return over the primary link...
To add to this, we have two inline firewalls on each link which are only performing IPS, no packet filtering.
Any pointers would be great.
thanks
Mario

Hi John,
right... please look at the output below which is the partial BGP table during a link failure...
10.128.0.0/9 is the problematic summary that still keeps getting advertised out when we do not want it to during a failure....
now there are prefixes in the BGP table which fall within that large summary address space. But I am sure that they are all routes that are being advertised to us from the eBGP peer...
*> 10.128.0.0/9     0.0.0.0                            32768 i
s> 10.128.56.16/32 172.17.17.241                 150      0 2856 64619 i
s> 10.128.56.140/32 172.17.17.241                 150      0 2856 64619 i
s> 10.160.0.0/21    172.17.17.241                 150      0 2856 64611 i
s> 10.160.14.0/24   172.17.17.241                 150      0 2856 64611 i
s> 10.160.16.0/24   172.17.17.241                 150      0 2856 64611 i
s> 10.200.16.8/30   172.17.17.241                 150      0 2856 65008 ?
s> 10.200.16.12/30 172.17.17.241                 150      0 2856 65006 ?
s> 10.255.245.0/24 172.17.17.241                 150      0 2856 64548 ?
s> 10.255.253.4/32 172.17.17.241                 150      0 2856 64548 ?
s> 10.255.253.10/32 172.17.17.241                 150      0 2856 64548 ?
s> 10.255.255.8/30 172.17.17.241                 150      0 2856 6670 ?
s> 10.255.255.10/32 172.17.17.241                 150      0 2856 ?
s> 10.255.255.12/30 172.17.17.241                 150      0 2856 6670 ?
s> 10.255.255.14/32 172.17.17.241                 150      0 2856 ?
i would not expect summary addresses to still be advertised if the specific prefixes are coming from eBGP... am i wrong?
thanks for everything so far...
Mario De Rosa

RDS Gateway Best practices Dual-Homed?

Good Day,
I am wondering what is a typical amount of time others see when end users launch a RemoteApp session that goes through the RDS Gateway.
Our two RDS Gateway servers (entire environment is W2k12R2) seem slow to me. They are both Dual-Homed and with a Nic on the DMZ and Internal side of the network. Maybe I would be better off disabling the Internal Nics and reconfiguring the firewall rules
so that everything routes through the DMZ nic?
Steve J.

Hi Steve,
Thank you for posting in Windows Server Forum.
Best practice for any server is depends on your environment scenario as you need to decide whether to place the gateway in DMZ or allow 443 to be opened to the internal network. Placing the RDS Gateway in DMZ is more secure, you can have more information from
beneath article.
RD Gateway deployment in a perimeter network & Firewall rules
http://blogs.msdn.com/b/rds/archive/2009/07/31/rd-gateway-deployment-in-a-perimeter-network-firewall-rules.aspx
For more detail and understand RD Gateway refer this article.
Hope it helps!
Thanks.
Dharmesh Solanki
TechNet Community Support
Please remember to mark the replies as answers if they help and unmark them if they provide no help. If you have feedback for TechNet Support, contact [email protected]

Dual-homed server to two Cat4948 switches

Hello everyone,
I have a picture above which I want to realize. The main point is a dual-homed server connected to two switches.
At server OS needed to configure NIC teaming which uses LACP. But how I can do it at Catalyst 4948?
Which technology I able to use to multi-switch etherchannel?
If I need one more link between Cat4948, then I can do.

The exact load sharing options available to you will probably depend on the server type / vendor. The settings are applicable to the Network Adapters but you usually use the configuration utility provided by the respective vendor. I would suggest you do a quick google search on your particular server model. An example is:
http://www.brianmadden.com/blogs/guestbloggers/archive/2006/04/19/hp-proliant-network-adapter-teaming-explained.aspx
Atif

Dual-homed FEX

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