CCIE path
Category: Certification — redwards @ 1:51 pm
I changed jobs 2 years ago and focus more on routing and switching (NMS/OSS now sits more on the hobby list) now so I decided to start up again on the Cisco certifications (thinking of others as well). This year I have completed CCDA, CCDP and just need to pass TSHOOT to gain full CCNP. I have enjoyed studying and learning all the technology’s and concepts so decided to try and get myself some numbers, yes I am looking at CCIE. While I was thinking how to break the learning into smaller chunks and also working out what I need to learning I thought it would be beneficial for me to blog about it! So watch this space.
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Cisco ISSU
Category: Networking — Tags: Cisco, ISSU, VSS — redwards @ 7:15 pm
During the building and configuration of a number of brand spanking new Cisco 6509′s with Sup720-3C I decided to convert them to VSS mode before updating the IOS (mainly due to laziness and only having console access). The conversion worked a treat however when I can to upgrade the IOS with ISSU I seemed to hit a glitch, the standby sup got itself in a reboot loop.
The error messages seen;
*Jul 26 14:38:21.291: %PFREDUN-SW1_SP-4-PHYSMEM_MISMATCH: Asymmetrical redundant configuration: Active SP has (1048576/8192K) memory, Standby has (1048576/65536K). *Jul 26 14:38:21.291: %PFREDUN-SW1_SP-4-PHYSMEM_MISMATCH: Asymmetrical redundant configuration: Active RP has (1048576/8192K) memory, Standby has (1048576/65536K). *Jul 26 14:38:22.307: %PFREDUN-SW1_SP-6-ACTIVE: Standby initializing for RPR mode *Jul 26 14:38:23.856: %ISSU-SW1_SP-3-FSM_MISMATCH_MTU: ISSU nego failed for client ISSU ifs client(110) entity_id 113 session 393699 due to mismatch of mtu size 72 & 36. : ios-base : (PID=12311, TID=17) : -Traceback=(s72033-advipservicesk9_wan-5-dso-bnp.so+0x94088) ([27:-3]4-dso-b+0x1ED79C) ([37:0]+0x1ED81C) ([27:-3]5-dso-bnp+0x908A4) ([39:0]+0x90B70) ([39:0]+0x91090) ([27:-3]6-dso-b+0x136110) ([27:-9]3+0x39F400) ([37:0]+0x36BF88) ([27:-9]7+0x1AA8A0) ([37:0]+0x1AA878) *Jul 26 14:38:23.892: %ISSU-SW1_SP-4-FSM_INCOMP: Version of local ISSU client ISSU ifs client(110) in session 393699 is incompatible with remote side. *Jul 26 14:38:23.892: %RFS-SW1_SP-3-START_NEGO_SESSION: RFS nego (393699:590199) to [issu:rfs:Secondary RFS Server Port:0x4050000] failed: [ISSU_RC_NEGO_ERROR]
After trying a couple of things (and not having patience) I decided to break out into ROMMON and reload with config-register of 0×2142 so that I could stop the roboot loop and put VSS into standalone mode. Although this worked a treat and I had both 6500 in standalone mode and with blank configuration (wr erase) I was unable to do anything on upgradeing the image as ISSU seemed to get stuck in it upgrade process;
Router#sh issu state detail
Slot = 5
RP State = Active
ISSU State = System Reset
Boot Variable = bootdisk:s72033-advipservicesk9_wan-vz.122-33.S
XI2a.bin,12;
Operating Mode = sso
Primary Version = bootdisk:s72033-advipservicesk9_wan-vz.122-33.S
XI2a.bin
Secondary Version = bootdisk:s72033-advipservicesk9_wan-vz.122-33.S
XI2a.bin
Current Version = bootdisk:s72033-advipservicesk9_wan-vz.122-33.S
XI2a.bin
Variable Store = PrstVbl
% Standby information is not available because it is in 'DISABLED' state
Router(config)#boot system flash sup-bootdisk:s72033-advipservicesk9_wan-vz.122-33.SXI2a.bin % ISSU process is in progress; Boot variable can not be updated.
Router#issu abortversion The system is without a fully initialized peer and Service impact will occur. Pr oceed with abort? [confirm] % ISSU process can be aborted only from [ Load Version ] or [ Run Version ] or [ Load Version - Switchover ] or [ Run Version - Switchover ] state
After trying a couple of command and looking on google I was no closer to getting the box back in a state that I could do anything with….until it dawned on me “I wonder if a clear command exists for ISSU to reset the flag”. Well yes it does;
Router#clear issu state
Router#sh issu state detail
Slot = 5
RP State = Active
ISSU State = Init
Boot Variable = bootdisk:s72033-advipservicesk9_wan-vz.122-33.S
XI2a.bin,12;
Operating Mode = sso
Primary Version = N/A
Secondary Version = N/A
Current Version = bootdisk:s72033-advipservicesk9_wan-vz.122-33.S
XI2a.bin
Variable Store = PrstVbl
% Standby information is not available because it is in 'DISABLED' state
Once I put the config-register back and added the required boot statement I was to a point in which I can reconvert the VSS.
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Fundamental Truths of Networking
Category: Networking — Tags: Network — redwards @ 4:29 pm
I have been meaning to put this one up for a while now, the end of April has reminded me of the April fools RFCs. Yes it is a bit sad to look forward to the April fool RFC – my favourite might well be the IP over Avian Carrier ones. I do think it is worth putting this one up again, especially on the last week or so I have had! I was tempted to issue it to a number of people ……
Network Working Group R. Callon, Editor
Request for Comments: 1925 IOOF
Category: Informational 1 April 1996The Twelve Networking Truths
Status of this Memo
This memo provides information for the Internet community. This memo
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.Abstract
This memo documents the fundamental truths of networking for the
Internet community. This memo does not specify a standard, except in
the sense that all standards must implicitly follow the fundamental
truths.
AcknowledgementsThe truths described in this memo result from extensive study over an
extended period of time by many people, some of whom did not intend
to contribute to this work. The editor merely has collected these
truths, and would like to thank the networking community for
originally illuminating these truths.
1. IntroductionThis Request for Comments (RFC) provides information about the
fundamental truths underlying all networking. These truths apply to
networking in general, and are not limited to TCP/IP, the Internet,
or any other subset of the networking community.2. The Fundamental Truths
(1) It Has To Work.
(2) No matter how hard you push and no matter what the priority,
you can’t increase the speed of light.(2a) (corollary). No matter how hard you try, you can’t make a
baby in much less than 9 months. Trying to speed this up
*might* make it slower, but it won’t make it happen any
quicker.(3) With sufficient thrust, pigs fly just fine. However, this is
not necessarily a good idea. It is hard to be sure where they
are going to land, and it could be dangerous sitting under them
as they fly overhead.(4) Some things in life can never be fully appreciated nor
understood unless experienced firsthand. Some things in
networking can never be fully understood by someone who neither
builds commercial networking equipment nor runs an operational
network.(5) It is always possible to aglutenate multiple separate problems
into a single complex interdependent solution. In most cases
this is a bad idea.(6) It is easier to move a problem around (for example, by moving
the problem to a different part of the overall network
architecture) than it is to solve it.(6a) (corollary). It is always possible to add another level of
indirection.(7) It is always something
(7a) (corollary). Good, Fast, Cheap: Pick any two (you can’t
have all three).(8) It is more complicated than you think.
(9) For all resources, whatever it is, you need more.
(9a) (corollary) Every networking problem always takes longer to
solve than it seems like it should.(10) One size never fits all.
(11) Every old idea will be proposed again with a different name and
a different presentation, regardless of whether it works.(11a) (corollary). See rule 6a.
(12) In protocol design, perfection has been reached not when there
is nothing left to add, but when there is nothing left to take
away.Security Considerations
This RFC raises no security issues. However, security protocols are
subject to the fundamental networking truths.
ReferencesThe references have been deleted in order to protect the guilty and
avoid enriching the lawyers.Author’s Address
Ross Callon
Internet Order of Old Farts
c/o Bay Networks
3 Federal Street
Billerica, MA 01821Phone: 508-436-3936
EMail: rcallon@baynetworks.com
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Intresting 6500 bug
Category: Networking — Tags: Cisco — redwards @ 8:33 pm
During some recent work we discovered a very interesting bug with Cisco 6500 and specifically their WS-X6708-10GE and WS-X6716-10GE cards. When installing the cards into 6509 or 6513 chassis it can cause an existing module to reload so if you happen to have chosen slot 9-13 you have a issue. The 8th slot above the one you install the card into will reload. So if you place in slot 9, slot 1 may reload. The interesting example I can think of is if you happen to be using a 6513 and install in slot 13 which slot is 8 above…..yes slot 5 which will be your supervisor card!
The bug details can be found below, however I like the workaround of powering the switch down to replace a hot swappable card.
CSCsz13049 W2.b: OIR 6708 to create bus stall in slot 12 cause reset on slot 4
Externally found severe (Sev2) bug: R-ResolvedThe release notes are:
Problem:
———
When a WS-X6708-10GE module or a WS-X6716-10GE module is inserted into a 6509 or 6513 chassis it may cause the module in slot N-8 to reload.
For eg. Insert into slot 9 may reset module in slot 1
Insert into slot 10 may reset module in slot 2
so on ..
Insert into slot 13 may reset module in slot 5There is no problem when removing the module from slots 9-13
Conditions:
———–
1. The 6708/6716 module should be inserted in slots 9 to 13.
2. Module insertion is done slowly.Workaround :
————1. Use slots other than 9 to 13 when inserting a 6708/6716 module.
or
2. Insert the module when the switch is powered down.As a workaround provided to previous customers that saw the exact problem, please refer to the following steps:
When seating the module, initially slide the module into the place, but do not let the locking arms close more than 45 degress. At this point the module is ready to be seated, but is not contacting the backplane.
When ready to fully seat the module, close the locking arms from the > 45 degree angle to fully closed. This must be done in less than 5 seconds. This should be easy to perform in less than 5 secs as the remaining angle for the arms are closed at steady rate.
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Config Register
Category: Networking — Tags: Cisco — redwards @ 4:39 pm
The other week I can across a very useful command after we had a failure to one of our Sup720 cards is a 6509′s. The card was replaced but during the boot-up it would keep on dropping back to ROMMON, however when you type ‘boot’ it would load as expected. When I was asked to have a look my immediate thought was ‘config register’ settings.
I carried out the usual configuration checks to ensure the config reg was set at 0×2102 (tried from both ROMMON and from IOS). When reloaded the same problem occurred with the output of the various IOS ‘sh’ (sh boot, sh ver) commands as well as commands form ROMMON showing things as OK. I then started to think we had a problem with the IOS image (even though I knew it was booting when I try manually), or the new card was faulty.
After a bit of digging and head scratching I discovered that I was getting misleading information from the ‘sh boot’ command as this did not give the answer for the Sup720 card, this was confirmed after issuing ‘remote command switch show boot‘ it showed the config register was et to 0×0. Issuing a config-register 0×2102 and rebooting resolved the issue.