Release Notes for Cisco IOS Release 15.6(1)M on the 5900 Series ESR Platforms

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Add 5Mbps and 100Mbps to the 5921

There are two new licenses that support additional throughput speeds on the 5921. The c5921 universalk9 and entbasek9 images now support the 5Mbps and the 100Mbps PIDs shown in the following table.

Performance Improvements on the 5921

The 50% CPU usage restriction on fast path thread has been removed. The IOS scheduler thread avoids going to sleep when it has a job, and improves the performance of c5921. This was previously tracked as bug #CSCuv60913 in the Closed Caveats section.

The Cisco 5921 ESR has the following limitation:

With the 5921 ESR, several situations have been encountered in which the e1000e Ethernet driver strips VLAN tags before a frame reaches the 5921. This will result in dot1q trunking not performing properly (the 5921 will receive frames with no VLAN tag, even though it is configured to expect VLAN tags). In IOS, you will notice this by seeing ARP or ping failures.
If you see such behavior, please issue the following debug command from IOS:

# debug arp

Now, try the ping again. If the VLAN tag stripping issue is present, you will see a "wrong cable" message similar to the following:

Now switch to the Linux command line and see if the e1000e driver is being used by issuing the following command (using eth0 as an example):

 

From the Linux command line, verify the VLAN mode of the device:

If the VLAN mode is enabled, this indicates that the driver is stripping the VLAN tags.

To remedy this using CentOS, please upgrade to the latest e1000e driver by following these steps from the Linux command line:

If the process ends with the following message, ignore it:

From the Linux command line, verify that the new driver has been activated:

 

Cisco IOS Release 15.6(1)M

The following sections list caveats for Cisco IOS Release 15.6(1)M:

Closed Caveats

• CSCuv60913

Symptom :

Minor performance improvement on the CPU utilization on the c5921.

Conditions :

Fast path thread goes to sleep when it utilize more then 50% of CPU.

• CSCuv01746

Symptom :

Physical interface configured under a certain VRF, breaks DLEP adjacency with radio device.

• CSCuj05125

Need to be able to change OSPFv3 metric OC

Symptom :

Router-dynamic cost for OSPFv3 = OC + (S1) + (S2) + (S3) + (S4)

Requests to be able to adjust the OC value

Workaround

OC is derived from the Maximum Data Rate (MDR). It would be much more meaningful to derive OC from the Current Data Rate and zero the remaining components of the metric calculation for MANET use here.

• CSCun78903

On the 5921 a memory leak over dlep session occurred when OSPF changed to EIGRP

Symptom :

While connecting with MANET infra server we will get a new virtual-access interface created every time for the same connection. The old virtual-access will still be there until you brought your router down or reboot.

• CSCur61052

When running DLEPv1.5, OSPF route cost was not being calculated as expected

Symptom :

When modem sends destination up message with the default link metrics value, the Route Cost doesn't change for new MANET neighbor.

• CSCus68229

Symptom :

On the 5915 series router running 15.2(4)GC2 IOS version, OSPFv3 is leaking memory.

• CSCut23386

Symptom :

IPv4 and IPV6 Multicast traffic does not pass through VMI interfaces. This happens only when Multicast traffic has to be forwarded over VMI interfaces.

• CSCut50780

Symptom :

Router crashes at bma_soutput

• CSCuv01746

Symptom :

Physical interface configured under a certain VRF, breaks DLEP adjacency with radio device.

• CSCuv60523

Symptom :

On the 5930, accurate accounting of CPU usage was not available.

• CSCuw11898

On the 5930, a crash leaded by BADSHARE messages occurred when shaping traffic

Symptom :

1. Apply a shaper on LAN interface that is oversubscribed by traffic coming in on a DMVPN tunnel

2. The following error messages may be seen

-Traceback= 58D6348z 4203E28z 4048508z 402CA64z 42409ACz 4019D24z 4019D24z 4240A68z 4225890z 4225890z 422C6F4z

*Feb 9 14:10:59.743: %SYS-2-BADSHARE: Bad refcount in datagram_done, ptr=12494B08, count=0

Open Caveats

• CSCuw55129

The c5921 is unable to read the VLAN tags from Linux kernel-2.6.32-504.23.4.el6.i686 and later, with one exception: using latest e1000 driver, 8.0.35-NAPI, with 2.6.36 kernel and dot1q works as expected.

Workaround :

No known workaround after kernel-2.6.32-504.23.4.el6.i686.

kernel-2.6.32-504.16.2.el6.i686 and Linux kernel 2.6.36 is working.

• CSCut75596

The 5940 needs to be able to limit the number of simultaneous login sessions per user. This applies to management connections via the VTY lines.

• CSCuv99496

CPU Utilization reaches 100% while running DLEPv1.7

Symptom :

May hit the problem when running the combination of DLEPv1.7, R2CP and PPPOE

Workaround :

None

• CSCuw64684

Packet loss observed during oversubscription of QOS in c5921

Symptom :

More packet loss is observed in all the queue on sending traffic using IXnetwork for QOS configuration

Conditions :

On oversubscribing a particular queue for example Q1

Workaround :

None

• CSCuu32711

DLEP cost not same on uut & neighbor router, after neighbors are brought up

Symptom :

After the DLEP client session is established, Configure OSPF and bring up the neighbors on uut and neighbor router. Once the VMI state changes to FULL on both sides, check the cost on both routers. The cost is not same on uut and neighbor router. It shows 1 on uut and 251 on peer router.

Workaround :

None

 

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

 

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