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evil_bunnY posted:2200 is still a bit stiff, but yeah there's little point to having a dude who could be billing 4 hours to another customer drive down to your office to change 2 lines on your external interfaces. Yeah, that's why you send an intern that is capable of breathing.
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Apr 13, 2012 04:22
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Tremblay posted:Yeah, that's why you send an intern that is capable of breathing.
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Apr 13, 2012 06:57
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I am in a cisco class, so I hope this is an appropriate place to ask this question. The chapter we are covering at the moment is all about OSPF. I felt all smug because I totally "got it" until I took the Cisco assessment. Now I am just confused! In any given multiaccess network, assuming all routers are running OSPF with the same area, should there not be only one Designated Router and one Backup Designated Router? I ask this because the assessment came out of no where with possible answers such as (pick three): HQ will be DR for 10.4.0.0/16. Router A will be DR for 10.4.0.0/16. HQ will be BDR for 10.4.0.0/16. Router A will be DR for 10.5.0.0/16. Remote will be DR for 10.5.0.0/16. Remote will be BDR for 10.5.0.0/16. In other words, there are separate DR and BDR routers for each network? Given that, I can understand the answers, but I am still stuck on my idea that within any area there should only be a single DR and a single BDR. I would repost the diagram/question verbatim but I am not sure that is kosher. This is a question for my instructor, I know, but the next class is our exam :/. I was feeling pretty chipper until I hit this.
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Apr 16, 2012 20:41
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Associate Christ
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CrazyLittle posted:There are third-party vendors who will be happy to take your money in exchange for software support!  Does such a thing really exist? I keep paying for Smartnet for fear that I'll need a software update.
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Apr 16, 2012 20:56
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Kaluza-Klein posted:I am in a cisco class, so I hope this is an appropriate place to ask this question. Only one BDR per Area, yes. Are you sure all networks are in the same area?
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Apr 16, 2012 21:02
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Might be thinking of the backbone area 0 instead of the hierarchical areas.
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Apr 16, 2012 22:09
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As far as I remember each broadcast domain holds a DR/BDR election so that question makes sense assuming this is the same topology I'm looking at, which I got by googling part of your question. e: So each segment has its own DR/BDR. I don't remember there being any limitations on how many DR/BDR pairs you can have in an area. You've only got one ASBR, and each sub-area probably has one ABR (obviously area 0 would have more if necessary) with the exception of that stub garbage, but I think those are the only area-specific limitations? Of course I could have just spouted enough bullshit for Cisco to come revoke my CCNA, which I feel would be entirely justified seeing as how I haven't used it in a year+ 
some kinda jackal fucked around with this message at 00:00 on Apr 17, 2012 |
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Apr 16, 2012 23:51
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bort posted:Software support? Yeah, I doubt they'll be supplying IOS images, but they'll be happy to take your money and maybe give some configuration support.
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Apr 17, 2012 00:14
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Most of the third party support vendors I've encountered will provide hardware replacement and configuration assistance. This is great until you run into a bug.
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Apr 17, 2012 00:49
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Martytoof posted:As far as I remember each broadcast domain holds a DR/BDR election so that question makes sense assuming this is the same topology I'm looking at, which I got by googling part of your question. Yes. Each broadcast domain elects a DR/BDR.
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Apr 17, 2012 03:12
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Jelmylicious posted:Only one BDR per Area, yes. Are you sure all networks are in the same area? It claims they are. Hopefully it is not too wrong to post the question text? "Refer to the exhibit. The routers in the exhibit are using default OSPF configuration settings to advertise all attached networks. If all of the routers start at the same time, what will be the result of the DR and BDR elections for this single area OSPF network? (Choose three.) " Google should find you the picture easy enough. Martytoof posted:As far as I remember each broadcast domain holds a DR/BDR election so that question makes sense assuming this is the same topology I'm looking at, which I got by googling part of your question. That makes sense, I suppose. My concern is that this is a very brief introductory chapter to OSPF and it has so far assumed that there is only one area and it doesn't even talk about hierarchies. And if each broadcast domain has a DR and BDR, wouldn't that mean each interface of a router/each network has a DR and BDR? How is that helping to cut down flooding?? I don't know what I am talking about.
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Apr 17, 2012 03:13
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Kaluza-Klein posted:And if each broadcast domain has a DR and BDR, wouldn't that mean each interface of a router/each network has a DR and BDR? How is that helping to cut down flooding?? It cuts down on flooding on the broadcast segment. Without DR/BDR elections every router on a broadcast segment would need to flood their updates to every other router on the broadcast subnet (we all love RIP right?). With DR/BDR the routers unicast updates to the DR/BDR who then multicast best paths down to the all-ospf-routers (224.0.0.5) multicast group. So on a 16 router segment, you're down to 12% of the original non-unicast traffic if you didn't have DR/BDR. -edit- correction, non-designated routers send advertisements to the all-designated-routers (224.0.0.6) multicast group (which the DR/BDR both join). -/edit- Also stop confusing dr/bdr with areas. dr/bdr are an optimization for broadcast networks, so no matter what area, or type of area, if a broadcast medium is involved there will be a dr/bdr election on each and ever broadcast segment. Also to return to the initial question, dr/bdr status is based on 2 things: 1) priority, priority always wins. 2) when priority is equal, highest OSPF RID wins. OSPF RID defaults to your highest loopback interface or, if no loopbacks are found, your highest numbered interface. So since it says default setting, the priorities are all 1, what are the RIDs? ragzilla fucked around with this message at 03:54 on Apr 17, 2012 |
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Apr 17, 2012 03:40
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Kaluza-Klein posted:And if each broadcast domain has a DR and BDR, wouldn't that mean each interface of a router/each network has a DR and BDR? How is that helping to cut down flooding?? When there are more than 2 routers on a subnet. Imagine if there were 5 routers connected in the same network via one switch, things would start getting very busy if all you had were L2 devices instead. ^^^That makes more sense than what I said, I wasn't even thinking about RIP Fatal fucked around with this message at 03:45 on Apr 17, 2012 |
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Apr 17, 2012 03:42
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Kaluza-Klein posted:That makes sense, I suppose. My concern is that this is a very brief introductory chapter to OSPF and it has so far assumed that there is only one area and it doesn't even talk about hierarchies. This is correct. In this instance the amount of areas is irrelevant. There can be 20 ethernet networks in area 0. As long as each network is its own broadcast domain then each network will elect a DR/BDR. The only places where the DR/BDR relationship doesn't happen is across p2p links (iirc). You may be confusing "network" with "area" in this instance, I can't be 100% certain but I think that might be the case. And your last question is exactly what happens (given a certain topology I mean, it's hard to be general about this). Assuming that they are the only two routers on the network then yes there is a chance that every interface will be brought up in a DR/BDR relationship. If there are three or more routers on that network segment then it depends entirely on the election process.  So here you have four separate networks, each one is in area 0 (not diagramed). Each link elects a DR/BDR because they are broadcast networks and they are the only two routers on each network.  If we throw a bunch of other routers onto the 10.0.3.0/24 network all of a sudden the need for a DR/BDR becomes evident. If you didn't elect two then all five routers would try to yak their route updates to each other. Obviously in this scenario I fixed the Router IDs so R3 and R4 would still be elected, but it could have easily been one of the others with a little priority tweaking. It may seem wasteful for each router to elect a DR/BDR on a two router network, but it's just infrastructure for a scenario where you'd add more routers. And honestly it's not really that wasteful. some kinda jackal fucked around with this message at 04:36 on Apr 17, 2012 |
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Apr 17, 2012 04:07
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Martytoof posted:It may seem wasteful for each router to elect a DR/BDR on a two router network, but it's just infrastructure for a scenario where you'd add more routers. And honestly it's not really that wasteful. It is wasteful (of link turn-up time). Which is why Cisco provides the wonderful 'ip ospf network point-to-point' command. We run this on all our p-t-p Ethernet links to suppress DR/BDR election.
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Apr 17, 2012 04:47
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I happily concede to someone with more practical experience in the field 
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Apr 17, 2012 05:08
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Anyone here have experience with circuit emulation? We're looking at the ASR 901 and/or MWR 2941 for RAN backhaul.
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Apr 18, 2012 20:02
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There was a post a while ago about being denied SW to fix a PSIRT issue. Just a heads up the policy is that fixed code will be provided for free regardless of contract coverage. If you get denied by the folks when you first call up the magic word is "Escalate".
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Apr 19, 2012 00:01
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What are the requirements for CompactFlash cards to work in Cisco devices? I'm specifically talking about a Sup720 in a 7606, I've got a 4GB Kingston card, formatted as FAT16, formatted in the supervisor in that chassis. I put an IOS image on it with my PC, it shows up fine on my PC, but I stick it in the supervisor and the card shows as empty! I then format the card in the supervisor again, stick it back in my PC and the IOS image is still there. I don't know how this could be happening. Do only specific cards work? Can anyone think of a way to explain what I'm witnessing? Can anyone recommend some 3rd party CompactFlash cards that will work and I can get quickly in the UK please? Edit: The device is currently running c7600s72033-adventerprisek9-mz.151-3.S2. Sir Sidney Poitier fucked around with this message at 08:06 on Apr 19, 2012 |
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Apr 19, 2012 08:03
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Anjow posted:What are the requirements for CompactFlash cards to work in Cisco devices? I'm specifically talking about a Sup720 in a 7606, I've got a 4GB Kingston card, formatted as FAT16, formatted in the supervisor in that chassis. I put an IOS image on it with my PC, it shows up fine on my PC, but I stick it in the supervisor and the card shows as empty! I then format the card in the supervisor again, stick it back in my PC and the IOS image is still there. I don't know how this could be happening. IME (based on ISR work) 4GB is pushing it. If you dir flash does it report a 4GB size? I used to find 4GB would report -3GB size What I used to do was use a Linux distro and partition it to a 512MB or 1GB size And the Sup720 maybe picky about what CF works
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Apr 19, 2012 10:17
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nzspambot posted:IME (based on ISR work) 4GB is pushing it. If you dir flash does it report a 4GB size? I used to find 4GB would report -3GB size 
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Apr 19, 2012 11:14
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I searched but didn't get much in the way of this so I thought I would ask... I'm considering picking up a SG300-10 or -20 just to gently caress around with on my home network. I want to start with VLANs, tagging ports, etc and just really see how much I can learn and get comfortable with. Is this a good switch for this? Anyone have any advice? It might be important to note that I am not living in the US right now so there is basically no secondhand market to get cheap IT gear on.
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Apr 19, 2012 16:29
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If you're looking for IOS experience you won't find it on the SG300 as they don't run it. You would almost certainly be better off trying to find a pair of secondhand 2950 switches, despite your location Are you looking to also use this at home like a normal switch? Because an IOS managed 10/100/1000 switch is going to set you back more than either of those.
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Apr 19, 2012 16:52
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hahaha holy gently caress, even on ebay the 8-port 2960g is $700 (seriously, don't buy this: http://www.ebay.com/itm/170827501321) CrazyLittle fucked around with this message at 19:12 on Apr 19, 2012 |
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Apr 19, 2012 19:08
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Posted this in the certification thread, but figure I'll post it here too since I haven't heard anything over there. Anyone have any guesses on when Cisco will be refreshing the CCNP? I need to renew my NA in the next year, so I should get cracking on it. I see the official Cisco cert library was released in early 2010. Is there any rumblings how how often they refresh and screw me out of $100 in books? I can probably take the CCNA Voice in the meantime since that book was put out about 6 months ago, and I don't expect it to be obsoleted for awhile. Ideas?
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Apr 19, 2012 19:23
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Surely a 2950 should be easilly found right? Every company I've worked for 2950's are sitting around and you can probably grab them for free. The old rear end routers are more expensive/rarer but simple switches should be easy to find.
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Apr 19, 2012 19:24
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Didn't Cisco just refresh the CCNP in 2008-abouts? I wouldn't expect updates anytime soon. That is to say, they went from BCMSN/ISCW/BSCI/ONT to ROUTE/SWITCH/TSHOOT and moved topics around. I doubt you'll be screwed out of books any time soon.
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Apr 19, 2012 19:51
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Powercrazy posted:Surely a 2950 should be easilly found right? Every company I've worked for 2950's are sitting around and you can probably grab them for free. The old rear end routers are more expensive/rarer but simple switches should be easy to find. Yeah, but he's looking at SG300 gigabit switches, hoping for IOS. Cisco Catalysts don't do full gigabit ports unless you're looking at a 2960G or better. 2950's are all FE + GE
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Apr 19, 2012 20:40
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Right I agree, but for home use 10/100 is fine. If he wants to learn IOS a 2950 should be great and it is still a passable switch for actual use.
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Apr 19, 2012 20:55
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Unless you have ears 
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Apr 19, 2012 21:00
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Quick question, say I have a subnet, 192.168.10.x/24 on two switches, and one server's faulty NIC is an APIPA address and starts a broadcast that floods the switches and brings the network down to a crawl, why would I not see this broadcast traffic in promiscuous mode on wireshark if I have a span session configured on the vlan?
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Apr 19, 2012 21:17
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Is your wireshark filter just missing the traffic? Are you looking at the unwrapped Frames at the IP Payload and just not seeing an APIPA address, or are you looking for "all broadcasts" and just not seeing the traffic?
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Apr 19, 2012 21:57
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CrazyLittle posted:hahaha holy gently caress, even on ebay the 8-port 2960g is $700 (seriously, don't buy this: http://www.ebay.com/itm/170827501321) I wasn't paying attention and accidently bought one of these the other day: http://www.ebay.com/itm/CISCO-Catalyst-3550-GBIC-12-Port-GIGABIT-SWITCH-WS-C3550-12G-/330718726981 I meant to get the 1000BASE-T version which is a C3550-12T. If any one knows of the a cheaper 1GbE switch that runs IOS, I would like to know.
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Apr 19, 2012 21:59
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You have the right destination port in your span session?
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Apr 19, 2012 22:01
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My Rhythmic Crotch posted:It might be important to note that I am not living in the US right now so there is basically no secondhand market to get cheap IT gear on.
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Apr 20, 2012 01:18
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2970G is the cheapest IOS running TX/copper switch that Cisco has. ~$300 ballpark used. WS-C2970G-24TS-E is 28 ports with four SFPs but is 1.5U.
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Apr 20, 2012 01:33
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Thanks for all the info and ideas guys. Getting some of this stuff in eastern Europe can lead to eye watering price tags. I'm not strictly tied to Cisco by any means (we use HP at work). As far as I know, those are the only two players in town. So I will keep checking around and investigating.
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Apr 20, 2012 08:34
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Powercrazy posted:Is your wireshark filter just missing the traffic? Are you looking at the unwrapped Frames at the IP Payload and just not seeing an APIPA address, or are you looking for "all broadcasts" and just not seeing the traffic? In wireshark I was capturing all traffic, no filters. I did see broadcasts but not anything coming from the faulty NIC. Link layer capture was ethernet. quote:You have the right destination port in your span session? Here is my span session details, 997 is the arbitrary vlan the traffic was on, wireshark was plugged into 4/9 Destination : Port 4/9 Admin Source : Port 3/5 Oper Source : None Direction : transmit/receive Incoming Packets: disabled Learning : enabled Multicast : enabled Filter : 997 Status : inactive <- was active at time of capture Also this particular problem is another example of why you don't run a layer 2 wan link, this broadcast traffic was flooding a TLS circuit killing their connectivity to their colo'd servers.
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Apr 20, 2012 14:18
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Powercrazy posted:Right I agree, but for home use 10/100 is fine. Not if you have a home server. Crushing a 100mbit connection is trivial for a single user to do moving large files around, gigabit not so much. A 10/100 switch will be fine to learn on, but no way in hell I'd actually put it in my home network in a place where I have to use it. Gigabit's still expensive enough at the business switch level that I can see why people don't do it there, but for home use where $35 D-Links are perfectly acceptable it's gigabit all the way.
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Apr 20, 2012 16:54
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Sometimes it's good to trawl Craigslist for Cisco equipment. I picked up two 1841, each fully populated with VWIC-2MFT-T1s a year or two ago for $400.
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Apr 20, 2012 19:22
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