Vlans and forwarding tables

on a switch with different vlans, does the switch have a different forwarding table for each vlan ?

Yes, see the link below which says:
"Note that most modern switches including the Catalyst 2900 XL, 3500 XL, 2940, 2950, 2970, 3550, 3750, 4500/4000, 5000, and 6500/6000 series switches maintain L2 forwarding tables per VLAN."
http://www.cisco.com/en/US/products/hw/switches/ps700/products_tech_note09186a00801d0808.shtml
Hope this helps. If so, please rate the post.
Brandon

Similar Messages

CEF and FIB - Also MPLS forwarding-table

Hi there,
I have been reading up on this but now i'm getting confused. My understanding so far is that CEF lookups increase layer 3 switching speed by making a copy of the routing tables next hops addresses and storing the information in the FIB and the mac addresses for the next hop interface is stored in the adjacency table both for fast lookups. Is the FIB table and adj table stored in the ASIC or does the ASIC just process the information?
My original research was to ascertain in which peice of hardware was the MPLS forwarding table stored, is this the same peice of hardware that the FIB table is stored in?

Hello Matt,
the route processor generates the FIB master copy that is then copied to locations in each linecard.
Each linecard can have multiple ASIC that access the local copy of the FIB. This happens in high end distributed architectures./platforms.
The TCAM ternary content addressable memory is a specialized type of memory that allows for efficient lookups of IP prefixes in the way it is organized and using the destination ip address as the search key.
Generally speaking, a software based router hosts the FIB in DRAM, TCAM are typically used in multilayer switch like C6500 or high end routers that have a distributed architecture.
And yes, the location of the LFIB the mpls forwarding table is the same, with the route processor building it and copies distributed to linecards. In this case the search key is an MPLS label not an IPv4 prefix.
see for C6500 architecture:
http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-6500-series-switches/prod_white_paper0900aecd80673385.html
Hope to help
Giuseppe

Sh mpls forwarding-table and IPv6

Hi,
I am running IPv6 over MPLS (not 6PE) but I cant see the bindings using "sh mpls ldp bindings" nor the forwarding info using "sh mpls forwarding-table", are these commands IPv4 only?
I can try: sh ipv6 cef, which gives me the info but in a different format.
Thanks for your help,
Roque

Roque,
I'm not sure I understand what you mean by IPv6 over MPLS if not 6PE. LDP or RSVP for ipv6 are not supported yet.
Could you please explain.
Regards,

Create 2 new VLANs and Trunk

Hi
I am working with a service provider to segment inbound traffic for a client. Rather than creating a seperate fibre circuit, we have opted for two new VLANs and a trunk to the upstream router.
The equipment we are working on is a Cisco Catalyst 2900XL, IOS (tm) C2900XL Software (C2900XL-H-M), Version 11.2(8)SA2, RELEASE SOFTWARE (fc1)
Current configuration:
version 11.2
no service pad
no service udp-small-servers
no service tcp-small-servers
hostname
enable secret
ip subnet-zero
ip domain-name
ip name-server
interface VLAN1
ip address
no ip route-cache
interface FastEthernet0/1
speed 10
duplex full
spantree portfast
interface FastEthernet0/2
speed 100
duplex full
spantree portfast
interface FastEthernet0/3
spantree portfast
interface FastEthernet0/4
shutdown
spantree portfast
interface FastEthernet0/5
shutdown
spantree portfast
interface FastEthernet0/6
shutdown
spantree portfast
interface FastEthernet0/7
shutdown
spantree portfast
interface FastEthernet0/8
shutdown
spantree portfast
ip default-gateway
snmp-server community private
snmp-server community public
line con 0
exec-timeout 0 0
stopbits 1
line vty 0 4
password
login
end
I need to creat VLAN 2 and VLAN 3. Traffic currently running through VLAN 1 will be segmented between these two VLANs with a trunk to an upstream router.
vlan database commands don't appear to be working. At this stage I only want to create the VLANs. Can anyone recommend a command reference?

Hi Paresh!
Good to hear from you!
User Access Verification
Password:
>en
Password:
#sh vtp status
^
% Invalid input detected at '^' marker.
It doesn't accept the command.
Here are the results of a show ? from enable mode:
publicswitch#sh ?
access-lists
accounting
aliases
arp
boot
buffers
cdp
clock
configuration
controllers
debugging
file
forward
history
hosts
html
interfaces
ip
line
location
logging
mac-address-table
memory
port
privilege
processes
queue
queueing
registry
reload
rhosts
rmon
running-config
sessions
snmp
spantree
stacks
startup-config
subsys
tcp
tech-support
terminal
users
version
Thanks

Problem in Selecting the data from EKPO and KONV tables

Hi Experts,
Presently I am working on Report with Comparision-Sheet Between the vendor's Quotations. I have to display the Discount, Freight, Packing and Forwarding, Vat in Item level data based on the conditions made in PO.
As per my Knowledge, Condition Types are stored in KONV Table. But there is no relation between KONV and EKPO tables. So, I am unable to print the data for Discount, Freight, Packing and Forwarding, Vat... How can I get the values from EKPO and KONV tables?
Thanks in Advance.
Thanks n Regards,
Muralikrishna.

Don't recall if this is correct, but you may need the condition number from the header (EKKO) combined with EKPO-EBELP or other field as you key to access KONV (KNUMH and KPOSN). My site doesn't run PP, so can't verify if the data is actually stored that, so just a possibility.

Updating bseg and bsis table ...

Hello,
I want to update bseg and bsis table. I guess i will have to use BAPI_ACC_DOCUMENT_POST.
how do i go on using this BAPI ? any starter code snippet ...!!

Functionality
Using this method you can create a posing in accounting for certain business transactions.
Possible ( Business Transactions):
Postings that generally only affect the general ledger. (RFBU)
Billing: For billing in Sales and Distribution, accounting is supplied with the relevant billing data. (SD00) Billing Document
Accounting can use the data of a logistics system that result from an Invoice Receipt. (RMRP)
Goods Movement are triggered by transactions in Sales and Distribution or by inventory postings. Within logistics, they lead to a change in the warehouse stocks of
<DS:GLOS.Inventory Management>Inventory Management. This results in a posting in accounting. This is why accounting is supplied with the relevant data from logistics. (RMWA)
Example
Billing document:
By selling goods in accordance with targets, revenue is generated. The revenue is posted in billing and forwarded
to accounting.
Invoice receipt:
Raw materials are purchased in accordance with targets. The invoice receipt is posted in a logistics system. The data from the raw materials is forwarded to accounting.
Goods Movment:
The use of raw materials leads to a change in stock in inventory managment. The posting of raw material consumption is forwarded to accounting.
G/L Account Posting:
Provision posting for an expected warranty service. This can refer to acquisitions or retirements belonging to stocks that are not in subledger accounting relevant to inventory management. This is particularly the case if such materials are not displayed as vendor/customer, materials, loans etc. or cannot be displayed in this way. This can also refer to write-ups or depreciation that contain higher aggregations of values than are maintained in a corresponding subledger that is relevant to inventory management.
The conversion of foreign currencies for receivables/payables due to large exchange rate changes that should not lead to an update of the accounts payable or accounts receivable accounting. A similar transaction can arise for the revaluation of raw materials if this revaluation takes place at a correspondingly aggreagated level.
Reclassification of inventory of P&L statement accounts that are only used for reconcilliation purposes in the general ledger (this rearranges values for balance sheet items).
Balance reclassifications of stocks to receivables with different return times.
Notes
If the parameter CurrencyAmount is filled with the currency fields, a complete document check including characteristics and value components of profitability analysis (CO-PA). Otherwise, the account assignment objects are checked.
Messages are returned in the parameter Return. In the parameter documentation you can find the return values and their meaning.

Link between vbpa and vbak tables

Hi,
I would like to know the link between VBAK and VBPA tables.
VBELN field in both these fields are the same?
If I give the VBELN field got from the VBAK table into the VBPA table will I get the customer number(KUNNR) of that particular SAles document?
Thanks & Regards,
Soumya.

You can get Kunnr directly from the VBAK table, if you wanna do the Join still you can go forward and do it there is no harm but remeber to give the Partner Function(PARVW) as well as VBELN.
Hope That Helps
Anirban M.

Question about the CSS behavior when using layer 3 sticky and sticky table

Hi everyone,
I have a question about the CSS behavior when using layer 3 sticky and sticky table is full.
If I configure layer 3 sticky and specify the inactivity timeout as below, how does the CSS
handle subsequent needed sticky requests ?
advanced-balance sticky-srcip
sticky-inact-timeout 30
CSS document says that
Note:
If you use the sticky-inact-timeout command to specify the inactivity timeout
period on a sticky connection, when the sticky table becomes full and none of
the entries have expired from the sticky table, the CSS rejects subsequent
needed sticky requests.
My question is what is the next reaction by doing the CSS if the CSS is in the
following condition:
when the sticky table becomes full and none of the entries have expired from
the sticky table, the CSS rejects subsequent needed sticky requests
Does CSS just rejects/drops subsequent needed sticky requests ?
or
Does CSS does not stick subsequence requests to particular service but CSS forward
subsequence requests with round-robin basis ? which means if the sticky table is full,
the CSS just works round-robin load balancing fashion for subsequence requests ?
Your information would be appreciated.
Best regards,

Hello,
There is a good document explaining this on Cisco web site
http://www.cisco.com/en/US/products/hw/contnetw/ps789/products_tech_note09186a0080094b4b.shtml
It depends if the sticky-inact-timeout is used or not. If not, it's FIFO (the oldest entry in the sticky table is removed). If yes, the CSS will reject the next sticky request.
Rgds,
Gaetan
Rgds
Gaetan

Cisco OTV Vlan Not Forward Capable

Hi All,
I am trying to setup OTV between two routers.
Using show otv adjacency I can see the other router with stat UP, But the VLAN I want to extend has NFC as its current state.
# show otv vlan
OTV Extended VLANs and Edge Device State Information (* - AED)
Legend:
(NA) - Non AED, (VD) - Vlan Disabled, (OD) - Overlay Down
(DH) - Delete Holddown, (HW) - HW: State Down
(NFC) - Not Forward Capable
VLAN Auth. Edge Device Vlan State Overlay
1200 inactive(NFC) Overlay1
I cannot find any documentation on this state and what it can be caused by.
Does someone know what can cause this state? What can I do to troubleshoot this?
This is my current config:
feature otv
otv site-vlan 1508
interface Overlay1
otv join-interface port-channel2
otv control-group 239.1.1.1
otv data-group 232.1.1.0/28
otv extend-vlan 1200
no shutdown
otv site-identifier 0x1508
Any help would be appreciated :)

Hello Tim
Brayton Hackworth had a similar post as yours, found here;
https://supportforums.cisco.com/message/3684179#3684179
Brayton is using the Mitel 5330 phones where the LLDP no longer fed VLAN information to the phone network. But, he reverted to use a DHCP server to provide the VLAN information.
Unfortunately, I (personally) cannot test any Mitel resources (since I don't have them) so my labs usually only consist of either 7900 series or SPA500/900 series phones.
The best thing I can really recommend to you is to make a package of data consisting of;
Topology which consists of;
Modem type
Router including IP
All devices including IP of switches
Servers / relevant workstations
# of attached devices and # of users on the LAN
Switch config file + show tech on a notepad
Syslog output from the switch
Working PCAP
PCAP showing failure
PCAP legend showing what IP address are who (unless topology contains all IP)
Where the PCAP is taken from and method
We then can create a service request for you and pass it for review.
-Tom

Find the list of forwarded workitems, forwarded by and forwarded to agents

Hi experts,
I want to find the list of workitems which were forwarded and the corresponding forwarded by and forwarded to agents.
The above requirement is for workitems of all kinds of status (might be completed, ready etc..)
Please suggest.
Regards,
Karthik

Thanks a lot vikram,
Hence the answer is refering to SWWLOGHIST table.
We need to pass the value 'SWW_WI_FORWARD' (which is an FM) to the field 'METHOD' of SWWLOGHIST table and get forwarded by and forwarded to agents from 'METH_USER' and 'PARA_VAL_1' fields for the worktiems in any date range.
Regards,
Karthik

Inter-VLAN routing, Auto-Voice VLAN and IP Address-Helper

Hope that somebody can help me with the setup in the screenshot.
Planning to use Auto-Voice VLAN and Smartports to configure VOIP
LLDP-MED will be enabled on the switch to detect the IP phones so they will be moved to the Voice VLAN (If not the first 6 signs will be added to the OID table). The Voice VLAN ID will be 2 >> Voice VLAN will be automatically enabled once a device is recognized as a IP phone right?
Workstations will be connected to the Cisco switch, VLAN data will be untagged and will remain on the native VLAN.
Smartports will be used to configure the ports (Macro's) >> Should configure the ports as trunks as assigns the correct VLANs right?
But how do i configure the IP Helper-Address? Do i have to create the Voice VLAN on both switches and then run the command "IP Helper Address" to specify a DHCP server? From what i've been reading it's required, when using Inter-VLAN routing, to configure the VLAN interface with an IP address. But it's going to give problems when both switches are connected to eachother and both have the same VLAN configured including the same IP address assigned to their VLAN interface?
Normal data should pass the ASA firewall, VOIP traffic should go through the Vigor modem to a hosted VOIP provider. The best way, i assume, is to configure 2 separate scopes on the DHCP server?
Still confused on how to set it up, hope that someone can point me in the right direction

If you're sending voice to only the Vigor modem then there is no need for a trunk between the SF-300 and the Vigor modem. You can just set that to an untag packet for the VLAN 2 between that switch and the Vigor modem.
On the 'edge' SF300 where the IP phone/PC is it is obviously going to interoute there and of course the phone port is tagged and PC port is untagged.
For the IP helper, it uses UDP-RELAY and it should be enabled on the port itself and enabled on the global configuration. You may also need option 82. Also keep in mind, depending how your DHCP server works, it may need option 82 configured as well or at least a route to understand the subnets in the layer 3 environment to get traffic across the VLANS.

VLAN and EBS

Hi,
i am using OEL 5.3 and have two nodes, one for db and other for apps. Due to security reasons i want DB-NODE be in different VLAN and apps in a different VLAN. during this test i didn't apply ACL on router, and no error in oracle apps/db logs. i am using Nortel Switch/Router.
the problem is when i change both nodes to different vlan, i am unable to view even login page of EBS app. even though no router envolment is there. both nodes are in single network 172.20.201.0/24 . no error in logs .
After this failure i changed the scenario and moved both nodes to single VLAN id=200. but same issue on this, no login page. then i rewerted both nodes to default vlan and default network and its working fine.
I want to know is there any problem with oracle EBS when working in VLAN?

Hi,
Can you ping the IP Address of the application/database nodes?
Can you ping the database server from the application node and vice versa?
There should be no issues in using different VLANs as long as all the nodes see each other. Just make sure you have proper entries in FND_NODES table and that AutoConfig run successfully on all tier nodes -- See (Note: 260887.1 - Steps to Clean Nonexistent Nodes or IP Addresses from FND_NODES).
Regards,
Hussein

Show tag-switching forwarding-table output

Hi
I'm doing a bit of mpls study and wondered if someone could confirm, or otherwise, my understanding of the LFIB table.
Local tag - The tag that this device would advertise upstream for a neighbour to use to get to a prefix ?
Outgoing tag - The tag I will apply as I send data downstream towards the destination ?
So for example prefix 10.1.1.0/24
Local tag 30 Outgoing tag 35. I put 30 on if I send to 10.1.1.0/24 and I advertise tag 35 to upstream neighbours to get to 10.1.1.0/24. Is that correct ?
What would pop tag mean in the outgoing tag column ? Would that be a PE telling a P to send untagged data because the PE is a neighbour with the CE advertising that prefix ?
Lastly what would the untagged and aggregate options mean ?
Thanks, Stephen.

Hello Steven,
>> Local tag 30 Outgoing tag 35. I put 30 on if I send to 10.1.1.0/24 and I advertise tag 35 to upstream neighbours to get to 10.1.1.0/24. Is that correct ?
It is just the opposite:
outgoing label = it is the label received by the device that is in the path to the destination prefix
local label= it is the label assigned by local node to the prefix and advertised to all LDP neighbors and used by neighbors that use local node to reach the destination.
if an MPLS frame with label 30 is received on an interface of local node it is swapped to label 35 and sent out the interface where this label binding has been received, that is on the best path to destination according to IGP metric.
the signalling protocol for MPLS builds other tables.
CEF builds the FIB forwarding information table.
LDP builds LFIB = label forwarding information table.
the routers in the MPLS cloud build LDP sessions between them.
In MPLS framed mode the labels are assigned in unsolicited mode: they are assigned to prefixes in the FIB before traffic for that prefix is seen.
Each router sends out its label assignments towards its LDP neighbors.
On each router each label value is used only once and associated to a prefix or other FEC.
the labels actually travel in the opposite direction of traffic: from nearest to farest node. Thi is called downstream.
unsolicited downstream indipendent
indipendent means that a node is free to associate a label to a prefix in FIB before receiving the label binding from the router that is on the path to the prefix.
note that all prefixes to be in CEF FIB have to be advertised by an IPV4 routing protocol like OSPF, EIGRP or IS-IS.
Also the LDP sessions are built using loopback interfaces so they can be setup only after the routing protocol convergence.
the end result that can be checked with
sh mpls forwarding
is that a local label is associated to the prefix,
the label received by the router upstream (nearest to the destination ) is used to send out MPLS packets
the local label is used by the router downstream (farer from destination) the current node when sending frame to this node
the mpls forwarding table says
if an incoming packet with label local-label is received I will send out a specific interface with label= action or outgoing label.
The edge nodes are the routers with at least one non mpls interface.
These nodes when sending traffic to a prefix perform label imposition by looking at LFIB if an entry is found is used to build the outgoing label.
when the edge routers receive packets destinated to their non mpls connected interaces they do the opposite by extracting the packet.
IOS uses normally penultimate hop popping: actually the last router before the edge node receives a special label (implicit-null) that instructs it to send packets for the prefix untagged to the edge node.
This is an optimization.
To be noted that MPLS support multiple label stacks and these are used for many applications: L3 VPN, L2 VPN, MPLS TE protection, 6PE, 6VPE.
when moving in the MPLS cloud only the more external label is changed at each node hop.
Inner labels travel unchanged end-to-end.
Hope to help
Giuseppe

Flexconnect AP - dynamic VLAN and local/central switched via radius possible?

Hello at all,
is it possible to tell a flexconnect ap if the client at a single ssid should get local switched or central switched and if central switched, which vlan it should use?
All I got so far was either central switched with dynamic vlan assignment or local switched with static vlan (because it falls back to the default static vlan configured at the ap if the radius assigned vlan doesn't exist), but I need a flexconnect ap that puts client a into the local switched vlan a and client b to the central switched vlan b, both in the same ssid. Is there a radius attribute to tell a flexconnect ap how to handle this while non flexconnect aps ignore it?
To be more detailed:
At the central location all APs are running in local-mode, radius assigns different vlans to the clients (different departments), lets say client a = vlan 100, client b = vlan 200 and this works fine. At the remote locations the APs are running in flexconnect-mode with default vlan 10 so that the authenticated clients can break out locally and use the local infrastructure for printing and file storage. At this locations radius also says client a = vlan 100, but client a should be forwarded to local vlan 10 (which already works because there is no vlan 100 configured at the ap so the default static configuration with vlan 10 is used), while client b should stay at vlan 200 and should be central switched to the controller because it isn't allowed to access the local infrastructure. How could this be done? Creating another ssid isn't a valid option.
Thank you,
Christian

Hi Christian.
This is what 7.3 mobility design document tells about "FlexConnect VLAN Based Central Switching" which is listed in above slide.
"From release 7.3 onwards, traffic from FlexConnect APs can be switched centrally or locally depending on the presence of a VLAN on a FlexConnect AP.
In controller software release 7.2, AAA override of VLAN (Dynamic VLAN assignment) for locally-switched WLANs puts wireless clients on the VLAN provided by the AAA server. If the VLAN provided by the AAA server is not present at the AP, the client is put on a WLAN mapped VLAN on that AP and traffic switches locally on that VLAN. Further, prior to release 7.3, traffic for a particular WLAN from FlexConnect APs can be switched Centrally or Locally depending on the WLAN configuration."
FlexConnect VLAN Central Switching Summary
Traffic flow on WLANs configured for Local Switching when FlexConnect APs are in connected mode are as follows:
•If the VLAN is returned as one of the AAA attributes and that VLAN is not present in the FlexConnect AP database, traffic will switch centrally and the client is assigned this VLAN/Interface returned from the AAA server provided that the VLAN exists on the WLC.
•If the VLAN is returned as one of the AAA attributes and that VLAN is not present in the FlexConnect AP database, traffic will switch centrally. If that VLAN is also not present on the WLC, the client will be assigned a VLAN/Interface mapped to a WLAN on the WLC.
•If the VLAN is returned as one of the AAA attributes and that VLAN is present in the FlexConnect AP database, traffic will switch locally.
•If the VLAN is not returned from the AAA server, the client is assigned a WLAN mapped VLAN on that FlexConnect AP and traffic is switched locally.
Traffic flow on WLANs configured for Local Switching when FlexConnect APs are in standalone mode are as follows:
•If the VLAN returned by the AAA server is not present in the FlexConnect AP database, the client will be put on a default VLAN (that is, a WLAN mapped VLAN on a FlexConnect AP). When the AP connects back, this client is de-authenticated and will switch traffic centrally.
•If the VLAN returned by the AAA server is present in the FlexConnect AP database, the client is placed into a returned VLAN and traffic will switch locally.
•If the VLAN is not returned from the AAA server, the client is assigned a WLAN mapped VLAN on that FlexConnect AP and traffic will switch locally.
Enjoy your weekend & I am sure you will be able to get this working.
HTH
Rasika
*** Pls rate all useful responses ****

Need help configuring multiple VLANs and SSIDs

Hi,
We bought a Cisco SGE2000P 24Port switch and 10 WAP4410N access points. Our intent is to provide a secure network to our LAN, and a guest network to the Internet.
We are thinking 3 VLANs would be best for this: VLAN 100 connected to the LAN, VLAN 1000 for the Internet Router and Filter, and VLAN 1100 for the Guest Wireless access.
We have the switch configured for all three of these, and 1 initial access point configured for the VLANS, too.
We have not yet moved the current Internet connection to VLAN 1000 because we aren't sure how to setup routing between VLANS.
Here are some specifics on how the traffic needs to route:
1. We have the DHCP server, which is the PDC, handling both scopes for the LAN and Guest VLAN.
2. The web filter in VLAN 1100 needs to authenticate with the DHCP server as there are different filter rules based on authenticated user. Any users coming from VLAN 1100 will have a default filter rule without requiring any authentication.
3. Certain traffic coming in from the Internet needs to be able to get to VLAN 100. The router has a built-in firewall that handles NAT and port forwarding, so as long as traffic can be forwarded to VLAN 100 we should be good.
4. Traffic on VLAN 1100 (guest Wireless network) should only be allowed to go to Internet (VLAN 1000).
Right now I have the VLANs configured and the ports assigned to the Access Points are set for TAGGED and on VLAN 100 and VLAN 1100.
The SGE2000P has the following IP addresses assigned to the VLANS:
10.7.3.252 - VLAN 100
10.7.40.254 - VLAN 1000
192.168.254.254 - VLAN 1100
Has anyone been able to setup a similar configuration? We have scoured the Internet for documentation but it seems to be very difficult to find!
Thank you!
Gary Smith

Based on your description of a 'Hybrid Port' this sounds like Cisco's 'Multi-VLAN Port' that was a feature of the 2900XL/3500XL series switches. This feature has however long since gone......
With a Cisco switch an access port supporting an Access VLAN & a Voice VLAN is effectively a Trunk with only one Tagged VLAN and the Native VLAN:
interface FastEthernet0/1
switchport mode access
switchport access vlan 10
switchport voice vlan 100
This results in the same configuration as:
interface FastEthernet0/1
switchport mode trunk
switchport trunk encapsulation dot1q
switchport trunk native vlan 10
switchport trunk allowed vlan 100
With the exception of CDP packets being sent advertising the Voice VLAN.
With regards to other IP Phone vendors and DHCP Vendor Options - the answer is it depends....
Nortel use Vendor Option 144 to inform the IP Phone of the Voice VLAN and Option 128 for the Server (PBX) to use. Ericsson uses Vendor Option 43 that can be configured to tell the IP Phone the VLAN and the Web server to read the config file from.
I don't think you will get this working automatically with your 3Com switches, you can however manually configure the VLAN on the Cisco IP Phones.
HTH
Andy

Vlans and forwarding tables

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