Trying to understand RSTP - Please can someone explain this?
Hi Group
I am still confused about how RSTP is implemented. From what i understand the major difference is that STP
used Timers for Loop prevention whereas RSTP coordinates between neighbors via messages (proposal/aggreement) to turn on links
more quickly after topology changes and is "timer free".
However, I have not noticed any difference in the configuration from the legacy STP
configurations and the RSTP configuration on cisco devices. Or are there any differences??
I have read in documentation that RSTP natively includes features like UplinkFast, BackboneFast and PortFast. So are these features now obsolete
and not needed to be configured if you are running RSTP. (Although i have seen Portfast still configured along with RSTP on many switches)
Also can someone explain the below Points from Cisco Documentation
1) should STP be disabled on edge ports all together as suggested below?
"STP edge ports are bridge ports that do not need STP enabled, where loop protection is not needed out
of that port or an STP neighbor does not exist out of that port. For RSTP, it is important to disable STP
on edge ports, which are typically front-side Ethernet ports, using the command bridge
bridge-group-number spanning-disabled on the appropriate interface. If RSTP is not disabled on edge
ports, convergence times will be excessive for packets traversing those ports."
2) It seems RSTP relies on duplex setting to determine inter-switch links. What is the configuration to explicitly
configure RSTP link types? (I couldnt find this in the documentation)
"RSTP can only achieve rapid transition to the forwarding state on edge ports and on point-to-point links.
The link type is automatically derived from the duplex mode of a port. A port that operates in fullduplex
is assumed to be point-to-point, while a half-duplex port is considered as a shared port by
default. This automatic link type setting can be overridden by explicit configuration. In switched
networks today, most links operate in full-duplex mode and are treated as point-to-point links by RSTP.
This makes them candidates for rapid transition to the forwarding state."
Also i am a bit rough on my RSTP knowledge even after skimming a few Cisco documents. Can someone please explain this in simple way.
Thanks in advance
to configure it on a device:-
spanning-tree mode rapid-pvst
PortFast/UplinkFast & BackboneFast were cisco "Enhancements" to 802.1d STP. RSTP just incorperates them. If you want to configure portfast, the command is still "spanning-tree portfast"
OK
1) That is your choice - I have bitter experiance of users/IT admins just plugging hubs/switches in when ever they can. Also cabling the switch back to itself creating a cabled loop. So my advice to you is to leave STP enabled on all switch ports, BUT enable BPDUGuard - this is a life saver, if you have configured portfast.
2) duplex auto! or duplex full (overiding)
I really suggest that you read the 802.1d standard, once you understand normal spanning-tree - RSTP will come to you.
http://www.cisco.com/en/US/tech/tk389/tk621/tsd_technology_support_protocol_home.html')">http://www.cisco.com/en/US/tech/tk389/tk621/tsd_technology_support_protocol_home.html')">http://www.cisco.com/en/US/tech/tk389/tk621/tsd_technology_support_protocol_home.html')">http://www.cisco.com/en/US/tech/tk389/tk621/tsd_technology_support_protocol_home.html
http://en.wikipedia.org/wiki/Spanning_tree_protocol')">http://en.wikipedia.org/wiki/Spanning_tree_protocol')">http://en.wikipedia.org/wiki/Spanning_tree_protocol')">http://en.wikipedia.org/wiki/Spanning_tree_protocol
HTH>
Similar Messages
-
I cant install or uninstall my itunes. I get this error 'the feature you are trying to use is on a network resource that is unavilable' Now ive seen the solutions on here but im using windows 8.1 and none of them work for me. Ive tried all options so please can someone help?
That doesnt work for me. I removed itunes through the windows cleaner method as shown in other posts and re-installed itunes. Now im getting this error
iTunes was not installed correctly. Please reinstall iTunes
Error 7 (Windows error 126)
Also my Microsoft office has stopped working after i deleted Itunes which is really strange.
Can somebody provide me a solution please.... -
Please can someone explain how to delete and email address that when typed in brings up one name but when you hit return to confirm it jumps to another name. I can't find them in my contacts list but they do come up when you type the first few letters of a name.
EG If I type xyz and the name of the person comes up, when I press return to confirm that's the one I want then it jumps to [email protected], always the same def address.
I can't fathom it out.
Thanks
TerriTry this:
Start a new email. In the To address bar, type in xyz like you normally do, press return to confim, and when the address you want to remove shows up in the address bar, move your cursor over the address you want to delete.
A small triangle next to the name will show up. click on it, a drop down menu will open, click Remove from Previous Recipients List. Then do the drop down menu again and Remove Address.
Good luck. -
HT3275 Please can anyone explain this to me
Please can anyone explain this to me - thank you -
Time Machine couldn't complete the backup to time capsule - The backup disk image “/Volumes/Data-1/Alyson’s iMac.sparsebundle” is already in use.The explanation is a long standing bug in Lion and Mountain Lion, but what you might really be asking is how to fix the problem.
Pull the power cord from the back of the Time Capsule
Wait a few minutes
Plug the power cord back in
If that does not fix the problem you will need to dig deeper. See #C12 in Pondini's excellent Time Machine - Troubleshooting.
http://pondini.org/TM/Troubleshooting.html -
Multithreading - Can someone explain this ...
Hi Java Gurus:
Can someone explain this to me why my multithreading worked in once case and not in the other.
First a little background:
My application lets the user create multiple JInternalFrames. Each frame has an OK button. When the user presses the OK button, the frame goes about it's business in a new thread, thus returning control to the use, so he/she can press the OK button on the second frame .. and so on.
Following is the event handler for the OK button that creates the new thread:
case1 - doesn't work:
btnTranslate.addActionListener(
new ActionListener() {
public void actionPerformed( ActionEvent e ) {
txtOutput.setText("");
txtBadParts.setText("");
Translation trans = new Translation(inst);
trans.run();
);case2 - works:
btnTranslate.addActionListener(
new ActionListener() {
public void actionPerformed( ActionEvent e ) {
txtOutput.setText("");
txtBadParts.setText("");
new Translation(inst).start();
);Thanks,
KamranCalling the run method makes the run method run in the current thread. You need to call the start method to get the thread to start its own thread.
-
Can someone explain this flashmo sample?
Hi,
I'm a newbie in flash and looking at this sample project.
http://www.flashmo.com/preview/flashmo_169_intro
I opened it with flash cs3, and can see actionscript on the actions layer, and can see symbols in the library. However, I cannot figure out what makes the symbols swoosh in/out in sequence. The actionscript on the actions layer does not have that, or so I figured.
Can someone explain where I need to look at?
Thanks.
BenThis is another good reason for never using scenes in Flash designs--they put things where they cannot be easily found. There is no actionscript for the animations, but there is a second scene that contains all of the animation. If you open the secnes panel you will find a second scene that includes all of what you are wondering about.
Ooops, sorry Rob. ....bad timing. -
HI,
CAN SOMEONE EXPLAIN TO ME THIS CODE:
FUNCTION DISP_QATD return VARCHAR2 is
BEGIN
SRW.REFERENCE(:P_CURRENCY_CODE);
SRW.REFERENCE(:P_QATD1);
SRW.USER_EXIT('FND FORMAT_CURRENCY
CODE = ":P_CURRENCY_CODE"
DISPLAY_WIDTH = "19"
AMOUNT = ":P_QATD1"
DISPLAY = ":DISP_QATD"
PRECISION = "STANDARD"');
RETURN(:DISP_QATD);
END;Hello,
For details about SRW.REFERENCE :
http://www.oracle.com/webapps/online-help/reports/10.1.2/topics/htmlhelp_rwbuild_hs/rwrefex/plsql/builtins/srw/srw_reference.htm?tp=true
Regards -
Can someone explain this difference in Mac vs Win policy ?
I can download a MathScript module for evaluation with the Windows evaluation version, but for the Mac, I have to first buy LabVIEW (the module is free, just can't be evaluated). Can someone explain the logic behind this nonsense ?
NI's activation platform doesn't work on the Mac or Linux operating systems. We created a "special" evaluation version of LabVIEW for the Mac, but after the 30 days, it requires you to uninstall it and install the regular version of LabVIEW, which doesn't have activation.
VISA is offered as a free download because it a device driver, and by practice, all of NI's device drivers are free. However, the MathScript RT Module is an add-on for LabVIEW. The reason that the Mac and Linux versions are free is because we don't have LabVIEW Real-Time for Mac or Linux, and the real-time capabilities for the LabVIEW MathScript RT Module are the primary reason for the cost of the Module in the first place. This ability to deploy custom .m files to embedded hardware, and run them deterministically, as well as the plug-in tools to do profiling and testing, is a huge differentiator for MathScript on the Windows platform. However, that functionality doesn't exist on the Mac or Linux platform.
The reason you can't download the Module is because we need to be able to track who the users are. Each new release of LabVIEW brings a new version of the MathScript RT Module, and we physically mail the new media to all of the users who have "purchased" the free Module, just like with any purchased Module. If we simply said go download it, then each person would have to go re-download it with each release.
"Go stuff yourself" is certainly not the intention. You will be able to use the Mac version of MathScript (free) on the evaluation version of LabVIEW for Mac. To find this version, navigate to http://www.ni.com/trylabview/ and choose to "See Download Options". The mac version is linked within this page.
I hope you find this information both helpful and satisfactory.
Jeffrey P.
LabVIEW Product Management
National Instruments -
Can someone please tell me how to retrieve deleted text. i was clearing old texts when a new one came through at the same time and was deleted also. My last update was iOS 8.1.2
You restore from a backup that was created after the text was received but before it was deleted.
But if you literally deleted it right after it came in, then it's not recoverable. Have the other person resend the text. -
Can someone explain this !!
Really it's amazing !
When I bought my E71 about 4 months ths ago ,and as I was upgrading from S40 series ,I found it a little bit slow , of couse compared to other N series like N73 it was much faster.
For some issues , I decided to hard reset the device ,When I did that , it got about twice the speed compared to the speed at the time of purchase !!
I said might be the programs , I started to install them one by one from my backup ,still the phone is much faster opening menus....etc compared to the time of purchase !!
I said might be other programs , and I took a brand new phone where I found the formatting removed some programs that were installed at phone memory like mmssync ,Nokia webservice support ,Nokia internet service support package 1 ...etc
I did that till I made sure from the file manager that my phone's programs are exactly the same as the brand new phone!
then I compared my phone , and a brand new phone taken from a friend's shop ,still my phone after formatting is much faster !!!
What can be the reason behind that ,really I am about to start telling all my friends to backup and hard reset to get the maximum speed , but will it work with everybody? ,I can't tell as I can't explain the phenomena at the first place... can anybody help ?Well, I have two E71s and I don't see this - one is still on the original firmware version and the other has been upgraded to the current version.
Now assuming that there is a difference between the firmware versions/programs installed, I would make a wild guess that in your original firmware, the factory installed format was sub-optimal. When you reflashed it, and reinstalled, you're probably seeing the effects of a better setup. But twice as fast is a little hard to believe.
Sanjay Mehta
Motorola "Brickphone" circa 1996, Alcatel One Touch, Ericsson R380, Sony Ericsson T220, Sony Ericsson T630, Nokia E50, Nokia E61i, Nokia 9300i, Nokia E71,Nokia X6, Google Nexus S, iPhone 4S -
Can someone explain this behavior?? (session 0 with htp.init)
Hi,
I've noticed that when you access a page using the Session 0 and that page contains an "htp.init" in a before header process, for some reason the session expires and creates a new one.
I made an example on apex.oracle.com, but first let me explain what've done exactly.
There's two pages. On page 1, I have an item named :P1_COLOR that is assigned the value of an application item :P_RED. This application item is affected in an application process before header that runs only on page 1 (the value assigned is "This is red"). I also have an item that displays the session id using this code:
return :APP_SESSION;
Then, I have a link called "page 2" in the HTML region :
a href="f?p=&APP_ID.:2:&APP_SESSION.:::::">page 2</a
Also, more importantly, on page 1 I have a process before header that sets a cookie:
begin
htp.init;
owa_util.mime_header('text/html', FALSE);
owa_cookie.send(
name => 'MY_COLOR_COOKIE_'||:P_RED,
value => 'test_value',
expires => SYSDATE365,+
path => null,
domain => null );
owa_util.mime_header('text/html', TRUE);
END;
Now if you go in the application normally without session 0, you will see the "This is red" with the session id and when you click on page 2 you will still see "This is red" with the same session ID
http://apex.oracle.com/pls/otn/f?p=60310:1::::::
But when using the Session 0, you see "This is red" with a session id, but when you click page 2, you don't see "This is red" and a new session ID is created, but the link in the address bar still contains the session 0. Also, if you press BACK and then go on page 2 again, you don't lose the :P_RED value nor the session. There seems to be a problem only the first time around.
http://apex.oracle.com/pls/otn/f?p=60310:1:0:::::
Can anyone explain me this behavior? Is it a bug? What is the work around? Because, i know that if you want to set a cookie you need "htp.init".
Note: I 've commented the cookie part of my process and only left the htp.init uncommented and had the same result, that's why I'm saying it is caused by htp.init
Thanks, reginald
Edited by: reggieh on Mar 19, 2009 7:09 AMYes, you might need to do something like that. The zero SID cookie is set only once: the first time the application is visited with a zero for session ID. So for email links where you use zero in the link, you could make the link target page a dummy public page (999) with BRANCH_TO_PAGE_ACCEPT in the request and the actual page you want the user to go to in the portion of the request after the pipe symbol, e.g., for page 10, the url would look like:
http://host:port:/pls/DAD/f?p=60310:999:0:BRANCH_TO_PAGE_ACCEPT|10
An after-submit process on page 999 would use :REQUEST as the page to redirect to:
owa_util.redirect_url('f?p=' || :APP_ID || ':' || :REQUEST || ':' || '0');
apex_application.g_unrecoverable_error := true;
If this works the way we're thinking, the zero sid cookie will be sent when page 999 is requested, then page 999's after-submit process would take the user to the desiired page on which your process could set the tracking cookie.
Scott -
I forgot my icloud password. I attemptted to reset it by going to my security questions and answering them but when I go to verify my birthday, it says
Please verify your birth date to continue.
Month January February March April May June July August September October November December Day 1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31 Year 2014
2013
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1983
1982
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
1956
1955
1954
1953
1952
1951
1950
1949
1948
1947
1946
1945
1944
1943
1942
1941
1940
1939
1938
1937
1936
1935
1934
1933
1932
1931
1930
1929
1928
1927
1926
1925
1924
1923
1922
1921
1920
1919
1918
1917
1916
1915
1914
1913
1912
1911
1910
1909
1908
1907
1906
1905
1904
1903
1902
1901
1900
1899
1898
1897
1896
1895
1894
1893
1892
1891
1890
1889
1888
1887
1886
1885
1884
1883
1882
1881
1880
1879
1878
1877
1876
1875
1874
1873
1872
1871
1870
1869
1868
1867
1866
1865
1864 For your security, please provide a longer answer.
Seriously how am I suppose to provide a longer answer?If you are having problems using the website to reset your password, you can call AppleCare support. They can assist you with AppleID issues, and I believe there will be no charge for that.
AppleCare phone number: (800)-694-7466 -
Please can someone explain what the firmware numbers me
Hi,
I would like to check whether I have the most up to date firmware for my Zen Micro but the number codes seem to be unfathomable. I have .02.05 and I don't need plays for sure because I don't use a subscription service. Is this the best one to have, because I am not sure if I still have the 24 hours standby mode before going into deep sleep, or whether I have the 4 hour.
Thanks
IsobelDitto on ..0.
On most Creative players with a choice of MTP (PlaysForSure) vs. non-MTP firmware--Micro, Sleek (the non-MTP version was in the initial European models; only MTP firmware is in US models or available for download anywhere), now Touch, and presumably Xtra when its MTP firmware releases--the .x.x line means non-MTP firmware; the 2.x.x line means MTP firmware. (The MicroPhoto is different, but from what I gather the non-MTP firmware on the first Singaporean models was a fluke.)
Within each line (as you can see from fred_be9300's changelog), the higher the middle numbers, the more recent the release. Thus ..0 is more recent than .0.02, which is in turn more recent than your current .02.05. -
Please can someone explain how to split a vertical a3 document into 2 horizontal a4 documents
Dear all,
I create .pdf documents using in-design and which are then displayed on a webpage and sent to clients.
The document currently is in the format shown below, however it is required for the .pdf to be in the format of two a4 documents rather than the one a3 document as shown. (The entire document is two a3 pages long and both pages need to be split in the same position (exactly 1/2 way down the height to make a4 pages)).
Thank you so much for any help! I will thank for helpful answers.
Yours Sincerely
James NurseCrop it in the middle. Remove the lower part. Save the upper half as one PDF.
Open the original. Crop it in the middle again. This time remove the upper part. Save the lower half as another PDF.
Merge the two files. -
Can someone explain this crazy query optimisation?
A software company has me trialling a product that has a query optimiser. I can't for the life of me explain what is going on below and would like some help from someone with a bit more SQL experience. I have a query I've been struggling to bring down the time on:
CREATE OR REPLACE VIEW PLATE_STATS_DATA_VIEW AS
SELECT P.Folder_ID, P.expt_or_control_ID, P.Plate_Type, P.Dose_Weight, P.Volume, P.Strain_Code, P.S9_Plus,
P.type_Name as Contents, P.Replicate_ID,
P.Number_Of_Plates, round(avg(P.count)) as mean_count,
min(P.count) as min_count, max(P.count) as max_count, count(P.count) as Plates_Counted
FROM expt_folder_plates P, History_Control_Log L
WHERE P.expt_or_control_ID = L.Control_ID
AND P.Strain_Code = L.Strain_Code
AND P.Plate_Type = L.Type_Code
AND P.S9_Plus = L.S9_Plus
AND L.control_Included > 0
GROUP BY P.Folder_ID, P.expt_or_control_ID, P.Plate_Type, P.Dose_Weight, P.Volume, P.Strain_Code,
P.S9_Plus, P.type_Name, P.Replicate_ID, P.Number_Of_PlatesIt took 20 seconds on my large test database, so I put it through the optimiser. It took it down to 0.1 seconds simply by changing 'WHERE P.expt_or_control_ID = L.Control_ID' to 'WHERE P.expt_or_control_ID = L.Control_ID + 0'.
I have no idea why this would make any difference - adding zero to a value?! Can anyone enlighten me?
Many thanks,
Gary
Message was edited by:
GaryKyleAhhh, thanks guys. I'm a bit of a beginner here. This is my first look at explain plans - just had to work out how to see them! I think I understand what is happening now - it looks like that with the index, it does the group by FIRST on all the data and this takes a large amount of time. Am I right?
Before +0:
SELECT STATEMENT, GOAL = ALL_ROWS Cost=162787Cardinality=1380965Bytes=328669670
SORT GROUP BY Cost=162787 Cardinality=1380965 Bytes=328669670
HASH JOIN Cost=16773 Cardinality=1380965 Bytes=328669670
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=EXPT_FOLDER_DETAILS Cost=29Cardinality=4038Bytes=387648
HASH JOIN Cost=16730 Cardinality=1380965 Bytes=196097030
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=AMES_PLATE_TYPES Cost=2Cardinality=6Bytes=192
HASH JOIN Cost=16715 Cardinality=1380965 Bytes=151906150
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=HISTORY_CONTROL_LOG Cost=2Cardinality=40Bytes=880
HASH JOIN Cost=16694 Cardinality=2002400 Bytes=176211200
HASH JOIN Cost=59 Cardinality=8076 Bytes=282660
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=EXPT_FOLDER_SOLVENTSCost=2Cardinality=3Bytes=51
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=CONTROLSCost=56Cardinality=8078Bytes=145404
TABLE ACCESS FULL Object owner=PI_AMES_BIGObject name=EXPT_FOLDER_PLATESCost=16584Cardinality=5499657Bytes=291481821After +0:
SELECT STATEMENT, GOAL = ALL_ROWS Cost=1655 Cardinality=138 Bytes=45954
HASH JOIN Cost=1655 Cardinality=138 Bytes=45954
HASH JOIN Cost=1625 Cardinality=138 Bytes=33672
HASH JOIN Cost=1569 Cardinality=414 Bytes=96462
MERGE JOIN CARTESIAN Cost=4 Cardinality=18 Bytes=630
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=EXPT_FOLDER_SOLVENTSCost=2Cardinality=3Bytes=30
BUFFER SORT Cost=2 Cardinality=6 Bytes=150
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=AMES_PLATE_TYPESCost=1 Cardinality=6Bytes=150
VIEW Object owner=PI_AMES_BIG Object name=TEST_PLATE_STATSCost=1564Cardinality=138Bytes=27324
SORT GROUP BY Cost=1564 Cardinality=138 Bytes=10350
TABLE ACCESS BY INDEX ROWID Object owner=PI_AMES_BIGObject name=EXPT_FOLDER_PLATESCost=39Cardinality=3Bytes=159
NESTED LOOPS Cost=1563 Cardinality=138 Bytes=10350
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=HISTORY_CONTROL_LOG Cost=2Cardinality=40Bytes=880
INDEX RANGE SCAN Object owner=PI_AMES_BIG Object name=EXPT_CONTROL_ID_INDEXCost=5Cardinality=248
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=CONTROLSCost=56 Cardinality=8078Bytes=88858
TABLE ACCESS FULL Object owner=PI_AMES_BIG Object name=EXPT_FOLDER_DETAILS Cost=29 Cardinality=4038Bytes=359382Thanks again,
Gary
P.S. looks like the explain plan's made the post horribly wide again ;) sorry. I'll keep it this way though otherwise the plan is hard to read.
Maybe you are looking for
-
Im trying to install windows 7 on my macbook air 13" where can i get the ISO image file?
i have no CD drive. i bought the macbook air in march right after spring break. so any help with getting the ISO. thanks in advance
-
Hi, I'm trying a Rmi implementation. The server side classes-interface look to work properly, but when I try to refer to remote objects from my client, it throws the following exception: java.rmi.UnmarshalException: error unmarshalling return; nested
-
Hello, I bought AP2 and upgraded towards AP3 (AP3.0.3 now - other information : french). During this time I just stored my photos. I've just created a web page with the "Publish to Mobile Me ..." button. The dialog box says that my page will be publi
-
Satellite A100 doesn't recognise Epson printer sx125
Hi Hoping someone can shed some light. Got a new printer Epson sx125 but having bother installing.. My laptop (Satellite A100) will not recognise it when I insert USB. I have updated drivers etc but nothing.. I tried the printer on computer upstairs
-
Bridge opens image files using Windows Photo viwer - not Photoshop CC. This is an utterly useless default setting. How do I get Bridge to open a file in Photoshop?