DLSw redundancy problem

| |
****** ******** | |
* *--CPA1--*7206-1*--| ******** |
*IBM * ******** |--*7206-3*--|
* * | ******** |
*HOST* | |
* * ******** |--******** |
* *--CPA2--*7206-2*--| *7206-4*--|
****** ******** | ******** |
| |
7206-1 and 7206-2 manage the the connection to the IBM host with a CPA card eich other.
7206-3 and 7206-4 manage the connection between the central site and the remotes sites via frame-relay network, they are border peer and DLSw load balancing coded. also manage the connection between a LAN of the central site and with bridge-group to reach an IBM HOST via 7206-1 and 7206-2.
The following is the configurations:
7206-3:
dlsw local-peer peer-id 3.3.3.3 group 3 border keepalive 0 promiscuous
dlsw load-balance round-robin
dlsw remote-peer 0 tcp 1.1.1.1 timeout 90
dlsw remote-peer 0 tcp 2.2.2.2 timeout 90
dlsw cache-ignore-netbios-datagram
dlsw bridge-group 1
7206-4:
dlsw local-peer peer-id 4.4.4.4 group 3 border keepalive 0 promiscuous
dlsw load-balance round-robin
dlsw remote-peer 0 tcp 1.1.1.1 timeout 90
dlsw remote-peer 0 tcp 2.2.2.2 timeout 90
dlsw cache-ignore-netbios-datagram
dlsw bridge-group 1
The probleme is:
In the central site, i see a slowness in the connection, and it is random, sometime a connction is very fast, other time it is very slow, and it can take up to 1,5 minute to connect.
After all that, i coded a dlsw redundancy in the 7206-3 and 7206-4 FastEthernets, the problem still exist in the LAN, and it cause a trouble in some remotes sites connected with frame-relay, that loose a connection to HOST.
Thank You for your help.

1. To make load balancing work you will have to add the following commands:
dlsw timer explorer-wait-time ...
source-bridge ring-group ...
Ring-group number must be the same on 7206-3 & 7206-4 - it prevents unnecessary explorer flooding.
2. If bridge-group 1 on 7206-3 & 7206-4 shares the same Ethernet domain you must use DLSw+ Ethernet Redundancy feature.
3. Border peers in the same group must be in full-mesh and all members in the group must peers with all border peers in this group. On 7206-3 & 7206-4 you will have to add the following commands:
(7206-3)# dlsw remote-peer 0 tcp 4.4.4.4 ...
(7206-4)# dlsw remote-peer 0 tcp 3.3.3.3 ...

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------------------ show running-config --------------
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http://www.cisco.com/en/US/products/sw/iosswrel/ps1612/products_feature_guide09186a0080080a6f.html
http://www.cisco.com/univercd/cc/td/doc/product/core/cis7505/rte_swit/6586rsp8.htm#213565

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Power Stack           Stack   Stack    Total   Rsvd    Alloc   Unused Num Num
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Powerstack-2          SP-PS   Stndaln 700     477     223     0       1    2
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Cosmetic bug
CSCui21029    3750X Stack no standalone stays in running configureation as standalone
Symptom:
When you are configuring a 3750x stack and initially putting it into a stack ring topology by configuring the following.
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Switch(config-switch-stackpower)#no stan
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Conditions:
3750X stacks with any license level
Workaround:
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How Clear the Session After we complete the Execution..
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I have several routers with dlsw feature.
Routers works properly yesterday but not today.
Someone complained to me why sna communication be delayed today?
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i found instatble of the Circuit.
circuit's uptime be reset...
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John

Thank you for replying.
The Topology is below.
HOST HOST
| |
|
4006 Switch
|
| |
Router1 Router2
| |
ATM ATM
| |
Router3
|
L2 Switch
|
SNA G/W
There are dlsw peer between Router1 and Router 3 and
Router 2 and Router3.
The Router 3 was configured loadbalancing(circuit-count) for sna traffic.
Acually, i found some abnormal history by using "show dlsw circuit history detail".
469762913 0060.9436.d70a(04) 4848.2424.1212(04) 172.20.52.231
Created at : 10:59:11.230 KST Mon Dec 13 2004
Connected at : 10:59:11.314 KST Mon Dec 13 2004
Destroyed at : 11:46:50.699 KST Mon Dec 13 2004
Local Corr : 469762913 Remote Corr: 704643190
Bytes: 86335174/88147104 Info-frames: 106541/108372
XID-frames: 5/4 UInfo-frames: 0/0
Flags: Local created, Remote connected
Last events:
Current State Event Add. Info Next State
CONNECTED DLC DataInd 0x0 CONNECTED
CONNECTED DLC DataInd 0x0 CONNECTED
CONNECTED DLC DataInd 0x0 CONNECTED
CONNECTED WAN ifcm 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED DLC DataInd 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN infoframe 0x0 CONNECTED
CONNECTED WAN halt-dl 0x0 HALT_PENDING
HALT_PENDING DLC DiscCnf 0x0 CLOSE_PEND
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Hi,
We have a RAC system which is running on Windows Server 2008 R2 and the oracle version is 11g.
When we close one of the nodes, other node can not take the sessions and loads then our database becomes unavailable.
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what version 11g??? ALWAYS POST THE FULL VERSION NUMBER. (and yes, I was yelling!!).
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Proper DNS configuration
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Do all the same rules apply when doing Dlsw redundancy with backup msfc's? For example, do I need the following types of commands:
dlsw transparent redundancy-enable xxxx master-priority x
and
dlsw transparent map local-mac xxxx remote-mac xxxx neighbor xxxx
and
dlsw transparent switch-support

Yes.
You may want to look into Single Router Mode (SRM) at http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_6_3/confg_gd/redund.htm for your MSFC redundancy. You lose MSFC load balancing but simplify the configuration greatly since you don't need to use HSRP or DLSw Transparent Redundancy.
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Eth. T/R DLSw w/ Redundancy

I have an ethernet segment and a Token Ring segment.
I have 2 routers connecting to both the Ethernet and the Token Ring. Both routers have a serial interface. I'm attempting to have dlsw redundancy for both Ethernet and Token Ring.
I noticed that when I 'Ping' from Ethernet to T/R, I get duplicate responses. I've been forced to disable redundancy for DLSw on the Token Ring. Is there any reason this might happen?
Any help will be greatly appreciated.

You may have a routing or bridging loop. It's difficult to troubleshoot on this type of message board. I'd suggest you open a case with the TAC and request some design help and configuration review. That way you can describe your specific situation and include diagrams of your network.

DLSW ER+ at the central site

The network topology that I have is two MSFCs and two external routers at central site and two MSFCs and two external routers at the remote site.
DLSW is activated on the external routers. In regards to DLSW+ ER at the central site, only one translational or transparent bridge can be active at a time. Manual intervention is required to cause a router to take over for the other router. Is there any other way to have some means of dlsw redundancy (w/o manual intervention) at the central site (for ethernet environment only)?
Second, DLSW ER+ cannot be deployed easily at the central site, since you need a lot of dlsw mapping. On the other hand, you also need local SNA PUs to be able and reach the CIP (both located at the central site) but reside on a different broadcast domain. Any ideas?
Thanks

Hi,
on the central side, host end, there are a couple of things you can do.
The potential solutions mentioned below are in the order that cisco would prefer.
1.
The most clean thing to do is to upgrade and configure the mainframe for appn and allow hpr/ip between the host end router and the host.
You will need to run dlsw/vdlc/snasw in the host end routers to be able to do this.
It also requires that you have ip connectivity to the mainframe.
If you do this than the mac address, the remote devices connect to, is configured as a snasw vdlc port in the routers. Both of them are active all the time, the remotes will learn the remote mac address over both peers and as such you have automatic, non manual intervention, redundancy, loadbalancing. The mac addresses in this case only exist in the central router. Nowhere else. The remote device does not know anything about this change.
Each of the head end dlsw/vdlc/snasw routers will have at least one hpr/ip uplink to the host. This is routed ip traffic into the mainframe.
In that case you can also define the physical ethernets as snasw ports, do hsrp on it and configure a hsrp mac address, this mac address would then be used as dmac for local clients connecting to the host.
2.
If for some reason you can not do the appn/snasw configuration you still have some options.
If you are using cisco cip's with csna today than you most likely have on path into the mainframe today for each mac address.
You can configure multiple vlans between the dlsw router and the cip router, i.e. dot1q trunk, and on the cip router you can configure multiple virtual ring groups and more than one csna path statement into the host. At the end you attach each vlan to one of the channel path, configure srtlb for each vlan into a unique vring, and then configure a different adapter number on each of the internal tokenring lans with the same mac address.
On the dlsw router you can configure multiple bridge groups into dlsw and each of those bridge groups goes to a different vlan. If you do this with two dlsw routers going to the same cip router you then end up with two channel access's and one vlan on each of the dlsw routers. If you do it to two cip routers you need 4 vlans. Just make sure that you dont bridge the vlans together.
The remotes learn than the remote mac address over both peers and your redundancy is established.
For the local clients this solution has the draw back that you need to pick a vlan where to connect them. There is no automatic redundancy, like hsrp in the first example, for those.
3.
You can enable both dlsw routers towards a single bridge-group and apply a mac address filter inbound to the bridge group only allowing the mac address/es of the hosts as source mac address.
That way you kill the potential loop on the head end. You will also need to put on as much restrictive filtering as possible to only allow the traffic that is wanted.
thanks...
Matthias

DLSw question

Dear all,
Could anyone help me to clarify the following point on DLSw redundancy?
Is it true if DLSw redundancy (or recover) are transparent to user if the end stations lie on a token ring network ? On the other hand if the end stations lie on the ethernet LAN, the DLSw can re-established itself but it is not transparent to user. Can I make such a conclusion ?
thanks

Hi,
no, this statement is not true.
From an end systems perspective the recovery is always disruptive. No matter if you are on a tokenring or on a ethernet lan.
That means:
DLSw is about llc2 sessions at layer2. If your lan attached end system has a llc2 session with a cisco dlsw router and i.e. that router fails, the llc2 session with the end system will fail aswell.
After the end system has realized that the llc2 session is gone it cleans up its local connections and then tries to reestablish the llc2 connection. If another dlsw router is available, who can reach the requested remote host, than this connection will come up again. That means the end user sna session goes down and comes back up again.
The same is true if you are talking about dlsw+ ethernet redundancy.
There is more in the details/differences between ethernet and tokenring lan segments. I.e. on a tokenring you have a rif in each packet which can be used for loop control.
On ethernet you almost always have ethernet switches, where a cam table of a ethernet switch in any vlan for any mac address can only point to exactly one port on the switch.
If you have two dlsw routers connected that can reach the same remote host those two routers will both send frames with the same host mac address into the same switch on two different ports. This is where dlsw ethernet redundancy feature comes into play.
thanks...
Matthias

DLSw - Backup Delay

I have DLSw redundancy configured. My circuits often drop from the primary dlsw peer and connect to the backup. I assume it's missing a certain number of responses back from the primary peer.
Is there a way to change the timers and cause the router to wait at least 60 seconds before switching over the backup dlsw peer?

Hi,
Configure this parameter...
Dlsw remote-peer 0 tcp x.x.x.x (primary peer)
Dlsw remote-peer 0 tcp y.y.y.y backup-peer x.x.x.x timeout Z
Z is the time after which, peering takes place over backup link.
x.x.x.x is primary peer
y.y.y.y is backup peer
Think this should work.

I have a problem for cisco catos 4232 switch.

i have entered the enable mode in cisco catos 4232 switch,but always there have been a remarks appearing all the time as follows:
2006 Feb 23 14:23:34 %SYS-4-P2_WARN: 1/Host 02:01:00:00:00:00 is flapping betwee
n port 3/34 and port 3/33
why?
thank you!
Best Respects!
guominquan

Hi Friend,
The message indicates that your Catalyst 4500/4000 switch has learned a MAC address that already exists in the content-addressable memory (CAM) table, on a port other than the original one. This behavior repeatedly occurs over short periods of time, which means that there is address flapping between ports.
If the message appears for multiple MAC addresses, the behavior is not normal
If the error message appears for one or two MAC addresses, locate these MAC addresses in order to determine the cause. Issue the show cam mac_addr command in order to identify from where these MAC addresses have been learned. In this command, mac_addr is the MAC address that the error reports as flapping.
After you determine between which ports this MAC address is flapping, track down the MAC address. Connect to the intermediate devices between your Catalyst 4500/4000 and the device that has the problem MAC address. Do this until you are able to identify the source and how this device connects to the network.
Note: Because the MAC address is flapping between two ports, track down both of the paths.
These are other issues that can cause this message to appear
1) Server NIC redundancy problem
2) HSRP
3) EtherChannel misconfiguration
4) Host reflects packets back onto the network
Check this link for complete details of this problem and how to troubleshoot
http://www.cisco.com/warp/customer/473/176.html#subtopic1k
HTH, if yes please rate the post.
Ankur

DLSw redundancy problem

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