Why access switch has flapping lead another distribution layer switch has root guard blocking and unblocking log

is it misconfiguration in Access Point's access switch or hacker attack from this switch?
many MATM-4-MACFLAP_NOTIF Host 0015.5dc1XXX VLAN 1 is flapping between port 1 and port 2
many MATM-4-MACFLAP_NOTIF Host 0015.5dc2XXX VLAN 1 is flapping between port 1 and port 2
many MATM-4-MACFLAP_NOTIF Host 0015.5dc3XXX VLAN 50 is flapping between port 1 and port 2
many MATM-4-MACFLAP_NOTIF Host 0015.5dc4XXX VLAN 50 is flapping between port 1 and port 2
last time we do not have these switch also meet the same issue about distribution layer switch have many ports down
last time someone mention a switch lost config, but today, i remember that the switch has reloaded and can be login again with radius,
today i do not connect any notebook with this switch and just have configured radius setting for window NPS radius server and then reload, then
i have dinner and come back and after a while, last time's issue happen again.
it seems port channel easy to have problem when abnormal traffic coming from access switch result in down port in distribution layer switch
i wonder whether someone can hack through the switchport access mode port and send some broadcast message

From that output and your description it looks like you have an STP issue as a result of misconfiguration somewhere.
Are your access points connected to switches with ports in access mode or trunk mode?

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Is there any reason why my ipad has 2 bars lte and my iphone 5 cannot keep lte in the same room?

I purchased my iphone 5 on release day and I purchased my ipad 3rd gen back about a year ago. Both are on verizon service. And both struggled at keeping an lte signal when i'm at work. I work in a metal roof building and I assumed that this was the issue. After several months I cancelled my service on the ipad. Last week I decided to reactivate the ipad. For some reason they decided to replace my sim card and gave me a new "phone number". When I carried it to work, i've had 2 bars lte coverage constantly. My iphone is still fluctuating from 3g to lte all the time. Most of the time it is stuck on 3g.
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Deleting a request in ODS that has no request number and monitor log

Hai All,
I have a request that failed. It oesn't even have a request id and is not getting deleted. Even if I delete it, the trash can symbol appears onits side and then disappears but the request still satys. I changed the status to red and deleted. Still its not getting deleted. There is no log in monitor also. I have a lot of data in the ODS and cannot afford to delete all data and load. Is there any table in SAP where I cn go in and delete it or is there any other way around?

Hello BI,
Please check the job logs in SM37 and see what job log says for deleting ODS request at the end though the job finished successfully. See if the job is still running in SM51 at the backend on server. If so please stop that job. I doubt that the request is still running either in R3 or BW in the backend. That could be one reason why it sometimes doesnt allow the request to be deleted.
Hope this helps,
Bye,
Naga.
Message was edited by: Naga Timmaraju

I can no longer access my verizon email account from my ipad-says there is a blocker and won't accept my password ?? how to fix

I can no longer access my verizon email account from my IPad - kicks my password out and says there is a blocker??how to fix?

Says there is a blocker?
Please provide the exact wording of the error message.
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Switch for Distribution Layer

I need your expert opinions for selecting a switch for distribution Layer
My requirement is 24Gig ports @ dist layer which will connect to 3750?s for server farm. I don?t want to negotiate with the bandwidth.
Which switch will be best for this scenario with max Backplane speed

Yes L3 routing will there.
I am considering 3750 for access switch for my server farm, and 4506 for distribution layer with the following port requirement
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Most of the gigabit port will be occupied since I have a huge server farm to connect. By using almost all the ports on 4506 will I be able to get the maximum through put??
I have not considered 6500 due to budget. If I consider 6500 will it be a good design to have 6500?s on both core and distribution layer

Stop broadcasts on edge access switches to a port

I have a telco person wanting to put the management port of their phone switch on to the network in one of our remote offices. They say that it will not handle broadcast very well and it will cause it to reset.
So is there a way to limit the broadcast traffic to the port the phoneswitch is connected to. Or is there another way to accomplish this.
using switches like edge access switches 3500XL, 2900XL, 3550 etc and or small routers like 1700 series.
Thanks.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_command_reference_chapter09186a008010f968.html
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Campus LAN Access Switch recommendation

Hi all,
I am looking at the specs of 2960X switches and 3750v2 switches as possible replacements for some old 3750 switches which are approaching End OF Support.
Am I right in understanding that the performance (both packet switching & backplane bandwidth) is better on the 2960X's than the 3750v2's? Although it looks like the 3750v2's are a lot more feature rich and also have dCEF.
The datacheets for the 2960X report 80gig Stacking bandwidth, and 216Gbps backplane bandwidth and at least 70mpps whereas the 3750v2's are only 32gig switching fabric bandwidth and a maximum forwarding rate of 13mpps! Is there something I am missing here??
I have no idea of costs, but just looking at getting the best value for money out of our Access Switches.
The 3650's and 3850's look good too but I imagine they are pretty costly compared to the 2960's and I do not think we need integrated WLCs in our access switches as the AP's we have in our building are minimal.
Any advice appreciated!
Thanks
Mario

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
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In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
BTW, you realize, 3750v2s are end-of-sale?
Correct, a 2960X might have higher fabric bandwidth and PPS ratings than a 3750v2, but that doesn't mean it's faster or better. For fabric bandwidths and PPSs, you need to look at the needs of the ports on the device.
A 3750v2 with 48 copper FE ports, and 4 SFP gig ports, has 8.8 Gbps of port bandwidth. So a non-blocking fabric needs to support 17.6 Gbps. As you note, the 3750v2 fabric is listed as 32 Gbps, so you're covered there.
The same 8.8 Gbps of port bandwidth needs up to 13.0944 Mpps (1.488 Mpps per gig) for wire-rate for minimum size Ethernet. Your noted 13 Mpps seems to cover that too.
So, basically, a 3750v2 switch is wire-rate capable.
When you get into stack bandwidth, even more that other switch parameters, there's lies, dam lies, and device performance specifications. Trying to judge one stack architecture against the other, gets very complicated very quickly.
On the 2960 series, I believe Cisco is "adding" each switch to switch ring link to an aggregate total. In an ideal situation, if traffic only needed to go from switch 1 to switch 2, and from switch 2 to switch 3, then the aggregate summation does have a bandwidth advantage over StackWise "bus" like ring usage. If traffic needs to go from between all 3 switches, traffic to from switch 1 to switch 3 will need to share the bandwidth also being used by traffic from switch 1 to switch 2.
I.e. a 2960 80 Gbps doesn't mean you get 80 Gbps between just two switches, or the advantage of all 80 Gbps found within a maximum member 2960 stack.
(As an aside, compare StackWise vs. StackWise Plus. The latter has twice the physical bandwidth, but it also operates much "smarter". Again, unwinding how stacks work, and their impact to your needs, is complicated.)
There's also more to a switch's performance than raw bandwidths and PPS rates. The switch's architecture, and other switch specifications, can make a big difference in real-world performance. You'll find 3560/3750s with the fabric bandwidths and PPS rates same as some 49xx switches, but the latter often will deal with busy servers much, much better, due to different port buffering.
All the above, also means, without some real analysis of both your needs and devices being considered, anyone's recommendations should be taken with a large grain of salt; including mine. ;)
That said, for simple L2 edge port usage, the less expensive 2960 series might be just fine for you. If you want to reduce costs even more, you might also look at Cisco's SMB switches, some I think are also now stackable.

HSRP between 2 access switches and 2 core switches

Hi I am looking for running HSRP between 2 access switches and 2 core switches for client PC and Server network’s next-hop redundancy as per attached setup.
As you can see I have used one /29 network for connecting CORE & ACCESS switches & configure Interface VLAN10 (Layer 3 SVI) with shown IPs and standby IP (VIP).G0/1 on Access Switches & G2/1 on Core Switches are access ports for VLAN10.
There is a L2 Trunk interconnecting Core-Main/Backup & as well as Access-Main/Backup Switches allowing VLAN10 to allow VLAN10’s HSRP packets to pass through (apart from other HSRP instances).
Below are the HRSP & Trunk configuration on Core and Access Switches please have a look and suggest if they are correct in term of HSRP implementation, as I can see on both side HSRP master & standby status are fine as desired, but I can’t ping VIP of ACCESS Switch from CORE switch, but the VIP of CORE switch I can ping from ACCESS switch.
Access-Main
interface GigabitEthernet0/1
description ***Connected to CR-SW-01 PORT G2/1***
switchport access vlan 10
switchport mode access
load-interval 30
interface GigabitEthernet0/2
description ***Connected to AC-SW-01 & AC-SW-02 for HRSP***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,40
switchport mode trunk
load-interval 30
interface Vlan10
description ***Connected to CR-SW-01 PORT G2/1***
ip address 10.10.11.1 255.255.255.248
standby 1 ip 10.10.11.2
standby 1 timers msec 200 msec 750
standby 1 preempt delay minimum 180
standby 1 authentication accvlan10
Access-Backup
interface GigabitEthernet0/1
description ***Connected to CR-SW-02 PORT G2/1***
switchport access vlan 10
switchport mode access
load-interval 30
interface GigabitEthernet0/2
description ***Connected to AC-SW-01 & AC-SW-02 for HRSP***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,40
switchport mode trunk
load-interval 30
interface Vlan10
description ***Connected to CR-SW-02 PORT G2/1***
ip address 10.10.11.3 255.255.255.248
standby 1 ip 10.10.11.2
standby 1 priority 10
standby 1 timers msec 200 msec 750
standby 1 preempt delay minimum 180
standby 1 authentication accvlan10
Core-Main
interface GigabitEthernet2/1
description ***Connected to AC-SW-01 PORT G0/1***
switchport access vlan 10
switchport mode access
load-interval 30
interface GigabitEthernet2/2
description ***Connected to CR-SW-01 & CR-SW-02 for HRSP***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20
switchport mode trunk
load-interval 30
interface Vlan10
description ***Connected to AC-SW-01 PORT G0/1***
ip address 10.10.11.4 255.255.255.248
standby 1 ip 10.10.11.5
standby 1 timers msec 200 msec 750
standby 1 preempt delay minimum 180
standby 1 authentication crvlan10
Core-Backup
interface GigabitEthernet2/1
description ***Connected to AC-SW-02 PORT G0/1***
switchport access vlan 10
switchport mode access
load-interval 30
interface GigabitEthernet2/2
description ***Connected to CR-SW-01 & CR-SW-02 for HRSP***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10,20
switchport mode trunk
load-interval 30
interface Vlan10
description ***Connected to AC-SW-02 PORT G0/1***
ip address 10.10.11.6 255.255.255.248
standby 1 ip 10.10.11.5
standby 1 priority 10
standby 1 timers msec 200 msec 750
standby 1 preempt delay minimum 180
standby 1 authentication crvlan10

Hi Rick thanks once again, so I am assuming I should use to configure as below and still one /29 subnet I can use to connect these Switches with the above static routings.
Access Switch-Main
interface Vlan10
description ***Connected to CR-SW-01 PORT G2/1***
ip address 10.10.11.1 255.255.255.248
standby 2 ip 10.10.11.2
standby 2 timers msec 200 msec 750
standby 2 preempt delay minimum 180
standby 2 authentication accvlan10
ip route 192.168.20.0 255.255.255.0 10.10.11.5
Access Switch-Backup
interface Vlan10
description ***Connected to CR-SW-02 PORT G2/1***
ip address 10.10.11.3 255.255.255.248
standby 2 ip 10.10.11.2
standby 2 priority 10
standby 2 timers msec 200 msec 750
standby 2 preempt delay minimum 180
standby 2 authentication accvlan10
ip route 192.168.20.0 255.255.255.0 10.10.11.5
Core Switch -Main
interface Vlan10
description ***Connected to AC-SW-01 PORT G0/1***
ip address 10.10.11.4 255.255.255.248
standby 1 ip 10.10.11.5
standby 1 timers msec 200 msec 750
standby 1 preempt delay minimum 180
standby 1 authentication crvlan10
ip route 192.168.40.0 255.255.255.0 10.10.11.2
Core Switch -Backup
interface Vlan10
description ***Connected to AC-SW-02 PORT G0/1***
ip address 10.10.11.6 255.255.255.248
standby 1 ip 10.10.11.5
standby 1 priority 10
standby 1 timers msec 200 msec 750
standby 1 preempt delay minimum 180
standby 1 authentication crvlan10
ip route 192.168.40.0 255.255.255.0 10.10.11.2

Spanning vlans across access switches in distribution block.... please help

Hi All
Can someone please explain why Cisco states that in a Campus Hierarchical modle if Vlans are spanned across Access switches in a distribution block, then the Distrubution to distribution link should be Layer 2. Is this really necesary or just a recommendation, and if so why? Can't this link be a L3 link when spanning vlans across Access switches in distribution block, as I understand the benefit of having a L3 distribution to distribution link so that SPT is avoided.
Please help

Hello,
The cisco recommended design is L3 links, but these is only possible if you have no vlans you need to span over the hole network.
It depends on your topology or what you want achieve.
If you need for one or more vlan's spanned the LAN, you need to use a layer 2 connection between all switches and between distribution too.
In my company we have for example a few vlans for restricted areas, like device management or else, so we can't use L3 Links in the distribution area because these vlan's are terminated at the firewall. I think these is good thing.
I would recommend you if you don't have to span one or more vlan's across the network to use L3 Links, specially in the case of redundancy way's. So you need no spanning-tree, but need to use other protocols like GLBP or else. The works faster and are not so confusing (for some people) as STP.
best regards,
Sebastian

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SSD and CFQ - why not, it has support for it

Hello,
in wiki its stated it is better to switch to deadline or noop instead of default cfq scheduler for SSD disks. But, I quote:
""CFQ has some optimizations for SSDs and if it detects a non-rotational
media which can support higher queue depth (multiple requests at in
flight at a time), then it cuts down on idling of individual queues and
all the queues move to sync-noidle tree and only tree idle remains. This
tree idling provides isolation with buffered write queues on async tree."
https://www.kernel.org/doc/Documentatio … osched.txt
So why change to deadline or noop?

Before discussing IO schedulers and what they are needed for let's look at a rotational device (HDD, spindle). Such device has spinning disks and head that physically moves to required location. Such structure leads to following characteristics:
- random latency it quite high, for modern HDD it is ~10ms (let's ignore disk controller write buffer).
- sequential access provides much higher throughput. In this case head needs to move less distance.
In case if we have a lot of running processes that make IO requests to different parts of storage (i.e. random access) then we can expect that a disk handles ~100 IO per second. Because modern systems can easily generate load much higher than 100 req/sec we have a queue of requests that have to wait for access to the storage. One way to improve throughput is to linearize access i.e. order waiting requests by its logical address and always choose closest request. Historically this was the first linux IO scheduler called elevator scheduler.
One of the problems with elevator algorithm is that it makes suffer processes with sequential access. Such processes read a block of data then process it for several microseconds then read next block and so on. Elevator scheduler does not know that the process is going to read another block nearby and thus to moves to another request at some other location. To overcome the problem anticipatory IO scheduler was added. For synchronous requests this algorithm waits for a short amount of time before moving to another request.
While these scheduler try to improve total throughput they also might leave some unlucky requests waiting for a very long time. Imagine majority of processes make requests at the beginning of storage space while an unlucky process makes process at the other end of storage. So developers tried to make algorithm more fair. Thus deadline scheduler was added. It has a queue ordered by address (the same as elevator). If some request sits in this queue for a long time then it moves to "expired" queue ordered by expire time. Scheduler check expire queue first and process requests from there and only then moves to elevator queue. It is important to understand that this algorithm scarifies total throughput for fairness.
CFQ (the default scheduler nowdays) aggregates all ideas from above and adds cgroup support that allows to reserve some amount of IO to a specific cgroup. It is useful on shared (and cloud) hostings - users who paid for 20 IO/s want to get their share if needed.
Now let's look at characteristics of SSD. It does not have moving parts. Random access as fast as sequential one. SSD can handle multiple requests at the same time. Modern devices' throughput ~10K IO/s that is higher than workload on most systems. Essentially user cannot generate enough requests to saturate SDD, the requests queue is effectively always empty. In this case IO scheduler does not provide any improvements. Thus it is recommended to use noop scheduler for SSD.
As for phoronix benchmarking - its results look sketchy to me. I would expect that noop is slightly better than deadline with difference at the measurement noise level.

Bandwidth from Access Layer to Distribution Layer

Folks:
I am currently on Chapter 12 of “CCNP Switching 642-813, Official Certification Guide” ISBN: 978-1-58720-243-8. I am currently not grasping the three layers entirely, and I was hoping someone could offer insight in a different way.
I believe I understand, that switches in the Access-Layer can be layer2 devices (2950, etc), and devices in the Distribution Layer should be Multilayer devices such as Layer-3 switches (3750) and inter-vlan routing takes place at the Distribution layer. But what I do not understand – how does one account for bandwidth and traffic from the Access Layer switches to the Distribution Switches?
Let use a 24 port 2950 switch located at the Access-Layer. If everyone was online and communicating, the total traffic for the switch would be 4.8 Gbps. The latter is due to each port providing 100 Mbps but in Full-Duplex, so (100*2)*24. So, how does an engineer spec out the required uplink ports from the Access Layer to the Distribution?
I am sure this is easy; however, I am not getting the concepts. Any insight is great.

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
As noted by Peter, edge hosts don't generally all concurrently push/pull their full port bandwidth for substained periods. However, host bandwidth usage often varies much by "kind" of host. For example, many server hosts are "busier" than most user hosts, so when designing networks you normally design for lower oversubscription ratios for server hosts than for user hosts. Old rule-of-thumbs ratios suggest oversubscription ratios of about 8:1 to 4:1 for servers, and about 48:1 to 24:1 for users.
Keep in mind that oversubscription ratios can be "skewed" by what the host is doing, i.e. not all server or user hosts have similar bandwidth demands. For example, your primary mail server or primary file server might be much "busier" than other server hosts. Likewise, some user hosts might be much "busier", for example, years ago I supported a LAN segment of CADD (20) workstations which had more traffic on their local LAN than the (2,000 user) corporate backbone.

Timed Access Switching Off??

My settings in Timed Access seem to hold for maybe a few days at a time, but then all of a sudden when I check it, the Timed Access tab reads Not Enabled.
No one else can be turning it off as I am the only one that knows the password.
Has anyone else experienced Timed Access switching itself off?...It is a useless feature if I can't rely on it to stop various devices from accessing my network at various times.

I can't find the links now that I'm specifically looking for them, but recall reading posts from several users who have posted over in the Lion forum with the same issue.
One user reported that after he reset the AirPort Extreme to factory default settings and then manually set it up again, that things worked fine.
it's a hassle to have to enter in all the Timed Access data again, but might be worth a shot. If you decide to try this, be sure to change the default rule in Timed Access (which allows all devices access).
It's best to set the default rule to "No Access" then enter in the specific MAC Addresses or AirPort IDs for devices. You've probably already done this in the past, but some users forget to change the "default" rule and then wonder why things don't work as expected.
No guarantees that this will work, of course. Up to you if you want to try.

Why access switch has flapping lead another distribution layer switch has root guard blocking and unblocking log

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