XenServer - CentOS 7 - Installer - Blank screen

Today I hit the issue AGAIN with XenServer 7.2 managed by XenCenter on Windows 10 and new VM with CentOS 7. I tried to perform minimal install of CentOS 7.x and after I created and started a VM I was seeing blinking text cursor on the blank black screen, nothing more. I hit the same issue few months ago and I don’t remember how I fixed it and I haven’t documented what I did so this time I had to find quick workaround. Google helped me with that - CentOS 7-1503 Installer gives blank screen:

• Start a new VM.
• Switch the the “Console” tab for the new VM. Install seems to stop at a blank screen with the blinking cursor.
• Close Citrix XenCenter.
• Re-launch XenCenter.
• Navigate back to the “Console” tab for the new VM. The Anaconda GUI is correctly presented!!!

Good luck!

DragonWave Horizon v1.x CLI commands.

Quick note about DragonWave Horizon Compact+ with software version 1.x.

DragonWave devices are well known for their problems with WebGUI, so it’s better to know how to check basic things via CLI.

Horizon Compact+, Release 1.3.10 (5845)
Copyright 2002-2015 DragonWave Inc.
All rights reserved.

Username :admin
Password :*************

->

From the prompt we see the model and SW version, but we can check SW version in details:

->get sw version

Horizon Compact+, OMNI Release: 1.3.10 (2015-12-22 12:26:01)

Software currently executing in system:

Component        | Version          | Validation
-----------------+------------------+----------------
Bootloader       | 1.2.2            |  Valid
Frequency File   | 2.01.32          |  Valid
MIB              | 6.0.0            |  Valid

->

To see active alarms we use “show alarms” or “get alarms” which is basically the same. Here is how it looks like when there’s no radio link (far end is having a problem).

->get alarms

Level Subsystem  Description                         Inst   Raised Time
----- ---------- ----------------------------------- -----  -------------------
Major Radio      RSL below threshold                 rf1   2019-01-22 21:28:33
Crit  Modem      Modem receiver loss of signal       mdm1  2019-01-22 21:28:11

->

Then we check receiving signal level. In this example far end is having an issue (basically no incoming signal).

->get modem statistics

Modem Performance Statistics:

Eb/No                   :   3.2 dB
Equalizer Stress        :     0
SNR                     :   4.6 dB
Receiver RSL            : -93.2 dBm

->

Here is how it would look like when we see incoming signal, but signal level is low, this is why modulation is low and we see active alarm:

->get modem statistics

Modem Performance Statistics:

Eb/No                   :  23.0 dB
Equalizer Stress        :    45
SNR                     :  24.4 dB
Receiver RSL            : -71.3 dBm

->get modem modulation
Modem Modulation Type  :64qam

->get alarms

Level Subsystem  Description                         Inst   Raised Time
----- ---------- ----------------------------------- -----  -------------------
Major Modem      HAAM operating in lower modulation  mdm1  2017-12-15 02:22:48

->

Normally you would not see any active alarms when signal is good, we have max modulation:

->get alarms
No Active Alarms Exist

->get modem statistics

Modem Performance Statistics:

Eb/No                   :  41.2 dB
Equalizer Stress        :    34
SNR                     :  42.6 dB
Receiver RSL            : -44.5 dBm

->get modem modulation
Modem Modulation Type  :2048qam

->

To check config summary:

->get system summary

Good luck!

Cisco Catalyst - Unsupported transceiver - GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR

For documenting purposes I will go ahead and put step-by-step procedure how to enable NON-Cisco SFP transceivers in Catalyst switches. In this test we will be using C3560G with 15.0(2)SE11 and generic Finisar MMF transceiver.

When you install NON-Cisco SFP you would see the following in logs:

*Mar  1 00:07:19.932: %GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port Gi0/49 has bad crc
*Mar  1 00:07:19.932: %PM-4-ERR_DISABLE: gbic-invalid error detected on Gi0/49, putting Gi0/49 in err-disable state

Here is how show interface output would look like. Interface will be in “err-disabed” state.

Switch#show int gi0/49
GigabitEthernet0/49 is down, line protocol is down (err-disabled)
  Hardware is Gigabit Ethernet, address is 0023.ab7d.76c1 (bia 0023.ab7d.76c1)
  Internet address is 1.1.1.1/24
  MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Auto-duplex, Auto-speed, link type is auto, media type is unknown
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out
Switch#

Transceiver will NOT be shown in inventory:

Switch#show inv
NAME: "1", DESCR: "WS-C3560G-48TS"
PID: WS-C3560G-48TS-E  , VID: V03  , SN: FOC1243W1GS

Switch#

Now let’s bounce the port to see if any difference:

conf t
 int gi0/49
  shutdown
  no sh

As the result, “err-disabled” state changed to down (notconnected)”:

Switch#show int gi0/49
GigabitEthernet0/49 is down, line protocol is down (notconnect)
  Hardware is Gigabit Ethernet, address is 0023.ab7d.76c1 (bia 0023.ab7d.76c1)
  Internet address is 1.1.1.1/24
  MTU 1500 bytes, BW 10000 Kbit/sec, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Auto-duplex, Auto-speed, link type is auto, media type is unknown
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out
Switch#

But link is not coming up. When you try to see signal level you get the following:

Switch#show int gi0/49 transceiver
Diagnostic Monitoring is not implemented.

Switch#

Next logical step is to apply two magic commands to allow NON-Cisco transceivers:

conf t
 service unsupported-transceiver
 no errdisable detect cause gbic-invalid

Port bounce will not change anything so you have a choice:
• Save the config and reboot the router.
• Physically pull the transceiver out of the chassis and plug it back in.

If you go the 2nd ways here is what you would see:

*Mar  1 00:12:24.748: %GBIC_SECURITY_CRYPT-4-VN_DATA_CRC_ERROR: GBIC in port Gi0/49 has bad crc
*Mar  1 00:12:24.748: %PHY-4-UNSUPPORTED_TRANSCEIVER: Unsupported transceiver found in Gi0/49
*Mar  1 00:12:30.268: %LINK-3-UPDOWN: Interface GigabitEthernet0/49, changed state to up
*Mar  1 00:12:31.275: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/49, changed state to up

Switch#show int gi0/49
GigabitEthernet0/49 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0023.ab7d.76c1 (bia 0023.ab7d.76c1)
  Internet address is 1.1.1.1/24
  MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive not set
  Full-duplex, 1000Mb/s, link type is auto, media type is unsupported
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:08, output 00:00:19, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     11 packets input, 4068 bytes, 0 no buffer
     Received 11 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 10 multicast, 0 pause input
     0 input packets with dribble condition detected
     1 packets output, 64 bytes, 0 underruns
     0 output errors, 0 collisions, 3 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out
Switch#

Interface came up, but still showing “media type is unsupported”, but it’s working and we can check optical signal level:

Switch#show int gi0/49 transceiver
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
If device is externally calibrated, only calibrated values are printed.
++ : high alarm, +  : high warning, -  : low warning, -- : low alarm.
NA or N/A: not applicable, Tx: transmit, Rx: receive.
mA: milliamperes, dBm: decibels (milliwatts).

                                 Optical   Optical
           Temperature  Voltage  Tx Power  Rx Power
Port       (Celsius)    (Volts)  (dBm)     (dBm)
---------  -----------  -------  --------  --------
Gi0/49       25.0       3.32      -4.9      -3.9   

Switch#

Moreover, unsupported transceiver showed up in “show inventory” output:

Switch#show inventory
NAME: "1", DESCR: "WS-C3560G-48TS"
PID: WS-C3560G-48TS-E  , VID: V03  , SN: FOC1243W1GS

NAME: "GigabitEthernet0/49", DESCR: "unsupported"
PID: Unspecified       , VID:      , SN: NSH1U19         

Switch#

After disconnecting fiber optic from the transceiver we noticed that it was showing -27.2. Cisco transceivers usually show -40.0. It probably depends on Transceiver model/vendor/firmware.

Switch#show int gi0/49 transceiver
ITU Channel not available (Wavelength not available),
Transceiver is internally calibrated.
If device is externally calibrated, only calibrated values are printed.
++ : high alarm, +  : high warning, -  : low warning, -- : low alarm.
NA or N/A: not applicable, Tx: transmit, Rx: receive.
mA: milliamperes, dBm: decibels (milliwatts).

                                 Optical   Optical
           Temperature  Voltage  Tx Power  Rx Power
Port       (Celsius)    (Volts)  (dBm)     (dBm)
---------  -----------  -------  --------  --------
Gi0/49       25.5       3.32      -4.9     -27.2   

Switch#

Good luck!

Cisco 10G SPA - Difference between WAN and LAN modes.

As you know, Cisco 10G SPA (Shared Port Adapter) modules could have two modes - WAN and LAN.

There’re actually two different modules:

• SPA-1X10GE-L-V2 (supports LAN mode only)
• SPA-1X10GE-WL-V2 (supports WAN and LAN modes)

CiscoASR#show inventory

NAME: "SPA subslot 1/2", DESCR: "1-port 10 Gigabit Ethernet Shared Port Adapter XFP based"
PID: SPA-1X10GE-L-V2   , VID: V02, SN: JAE1325CKI7

NAME: "SPA subslot 1/3", DESCR: "1-port 10 Gigabit Ethernet Shared Port Adapter XFP based"
PID: SPA-1X10GE-WL-V2  , VID: V01, SN: JAE14063H6T

By default, WAN-capable modules are in WAN mode. If you have two SPA-1X10GE-WL-V2 modules and trying to make a link between each other it will be no problem, but when you connect SPA-1X10GE-WL-V2 to any other regular 10G ethernet port (to your uplink provider or to any other 10G ethernet router/switch, etc) the link will not come up.

Unfortunately, “show interface” output doesn’t tell you anything other than the link is down and hardware is SPA-1X10GE-WL-V2. What you can do is to check incoming optical signal level to make sure it’s not an issue with remote side or transceiver:

CiscoASR#show hw-module subslot 1/1 transceiver 0 status
The Transceiver in slot 1 subslot 1 port 0 is enabled.
  Module temperature                        = 27.238 C
  Transceiver Tx bias current               = 6800 uAmps
  Transceiver Tx power                      = -2.1 dBm
  Transceiver Rx optical power              = -2.5 dBm
CiscoASR#

You can also check optical signal level on peering device. In my case it was Cisco Nexus:

N5K-1# show int eth1/9 transceiver details
Ethernet1/9
    transceiver is present
    type is 10Gbase-SR
    name is CISCO-FINISAR
    part number is FTLX8571D3BCL-C2
    revision is A
    serial number is FNS15531MJA
    nominal bitrate is 10300 MBit/sec
    Link length supported for 50/125um OM2 fiber is 82 m
    Link length supported for 50/125um OM3 fiber is 300 m
    Link length supported for 62.5/125um fiber is 26 m
    cisco id is --
    cisco extended id number is 4

           SFP Detail Diagnostics Information (internal calibration)
  ----------------------------------------------------------------------------
                Current              Alarms                  Warnings
                Measurement     High        Low         High          Low
  ----------------------------------------------------------------------------
  Temperature   37.64 C        75.00 C     -5.00 C     70.00 C        0.00 C
  Voltage        3.28 V         3.63 V      2.97 V      3.46 V        3.13 V
  Current        7.99 mA       11.80 mA     4.00 mA    10.80 mA       5.00 mA
  Tx Power       -2.29 dBm       1.69 dBm  -11.30 dBm   -1.30 dBm     -7.30 dBm
  Rx Power       -3.01 dBm       1.99 dBm  -13.97 dBm   -1.00 dBm     -9.91 dBm
  ----------------------------------------------------------------------------
  Note: ++  high-alarm; +  high-warning; --  low-alarm; -  low-warning

N5K-1#

The next step is to check current mode:

CiscoASR#show controllers wanphy 1/1/0
TenGigabitEthernet1/1/0
Mode of Operation: WAN Mode
SECTION
  LOF = 2             LOS    = 1                            BIP(B1) = 19
LINE
  AIS = 2             RDI    = 0          FEBE = 0          BIP(B2) = 3842
PATH
  AIS = 2             RDI    = 0          FEBE = 4          BIP(B3) = 4
  LOP = 0             NEWPTR = 0          PSE  = 0          NSE     = 0
WIS ALARMS
  SER    = 2          FELCDP = 1          FEAISP = 1
  WLOS   = 1          PLCD   = 0
  LFEBIP = 569        PBEC   = 4         

Active Alarms[All defects]: SWLOF LAIS PAIS SER
Active Alarms[Highest Alarms]: SWLOF
Alarm reporting enabled for: SF SWLOF B1-TCA B2-TCA PLOP WLOS 

  Rx(K1/K2): 00/00  Tx(K1/K2): 00/00
  S1S0 = 00, C2 = 0x1A
PATH TRACE BUFFER: UNSTABLE
  Remote J1 Byte : 

BER thresholds:  SD = 10e-6  SF = 10e-3
TCA thresholds:  B1 = 10e-6  B2 = 10e-6  B3 = 10e-6

CiscoASR#

To switch to LAN mode:

CiscoASR#conf t
CiscoASR(config)#hw-module subslot 1/1 enable lan

3378009: Jan 15 2019 19:02:33.081 PST: %IOSXE_OIR-6-SYNCSPA: SPA (SPA-1X10GE-WL-V2) reloading to come up in LAN mode
3378010: Jan 15 2019 19:02:33.287 PST: %IOSXE_OIR-6-SOFT_RELOADSPA: SPA(SPA-1X10GE-WL-V2) reloaded on subslot 1/1
3378011: Jan 15 2019 19:02:33.291 PST: %SPA_OIR-6-OFFLINECARD: SPA (SPA-1X10GE-WL-V2) offline in subslot 1/1
3378012: Jan 15 2019 19:02:41.898 PST: %SPA_OIR-6-ONLINECARD: SPA (SPA-1X10GE-WL-V2) online in subslot 1/1
3378013: Jan 15 2019 19:02:41.939 PST: %IOSXE_SPA-6-UPDOWN: Interface TenGigabitEthernet1/1/0, link down due to remote fault
3378014: Jan 15 2019 19:02:43.713 PST: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/1/0, changed state to down
3378015: Jan 15 2019 19:02:44.703 PST: %IOSXE_SPA-6-UPDOWN: Interface TenGigabitEthernet1/1/0, link down due to remote fault
3378016: Jan 15 2019 19:02:43.936 PST: %LINK-3-UPDOWN: SIP1/1: Interface TenGigabitEthernet1/1/0, changed state to down
3378017: Jan 15 2019 19:02:47.543 PST: %LINK-3-UPDOWN: Interface TenGigabitEthernet1/1/0, changed state to up
3378018: Jan 15 2019 19:02:46.700 PST: %LINK-3-UPDOWN: SIP1/1: Interface TenGigabitEthernet1/1/0, changed state to up
3378019: Jan 15 2019 19:02:48.544 PST: %LINEPROTO-5-UPDOWN: Line protocol on Interface TenGigabitEthernet1/1/0, changed state to up

Here is how it looks like in LAN mode:

CiscoASR#show controllers wanphy 1/1/0
TenGigabitEthernet1/1/0
Mode of Operation: LAN Mode

CiscoASR#

More information about WAN-PHY and LAN-PHY can be found in Datasheet for Cisco 1-Port 10 Gigabit Ethernet LAN/WAN-PHY Shared Port Adapter and Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide:

Overview of LAN/WAN-PHY Controllers

LAN/WAN-PHY support in Cisco IOS XE Software Release 3.3.0S and later is based on the IEEE 802.3ae standard. WAN-PHY controllers can only be used as Path Terminating Equipment (PTE). When deploying Ethernet WAN interfaces as endpoints or as PTE between routers, the other endpoint must be an Ethernet WAN interface. WAN-PHY does not interoperate nor terminate on a Packet over Sonet (PoS) or an Ethernet over Sonet (EoS) port.

The purpose of WAN-PHY is to render a 10-Gigabit Ethernet compatible with the SONET STS-192c format and data rate, as defined by ANSI, as well as the SDH VC-4-64c container specified by ITU. To achieve this compatibility, a WAN Interface Sublayer (WIS) is inserted between the 10-Gigabit Ethernet Physical Coding Sublayer (PCS) and the serial Physical Medium Attachment sublayer/Physical Medium Dependent sublayer (PMA/PMD). When the controller is in WAN-PHY mode, the WIS sublayer transports 10-Gigabit Ethernet frames in an OC-192c SONET payload that can interoperate with SONET section or line-level repeaters. This effectively bridges the asynchronous world of Ethernet data with synchronous SONET/SDH transport, allowing the 10-Gigabit Ethernet to be transparently carried over current DWDM networks without having to directly map the Ethernet frames into SONET/SDH.

Following is a list of the WIS characteristics and the functions it performs:

• The WIS allows WAN-PHY equipment to generate an Ethernet data stream to be mapped to an OC-192c or VC-4-64c concatenated payload at the PHY level without any MAC or higher layer processing.
• A 10GBASE-W interface cannot interoperate directly with SONET or SDH equipment because WAN-PHY is not fully compliant with SONET or SDH optical and electrical specifications. In practice, SONET or SDH and 10GBASE-W interfaces can interoperate.
• From a MAC perspective, WAN-PHY does not appear any different from LAN-PHY (no WIS) with the exception of the sustained data rate. In the case of LAN-PHY, the maximum data rate is 10.3125 Gbps, while at WAN-PHY, it is 9.95328 Gbps (as required by SONET or SDH).
• The WIS implements a subset of the SONET functions, including creating the section, line, path overhead headers, calculating the Bit Interleaved Parity (BIP) bytes for error monitoring and managing a variety of alarms and defect indications.

Good luck!

Cisco IOS - BGP - set as-path prepend last-as [EXPLAINED]

This post is for those engineers who want to elaborate more universal configuration to do BGP AS_PATH prepending by using “set as-path prepend last-as” parameters. You should know that “set as-path prepend last-as” skips your own BGP AS and works only on transit AS. If you’d like to add your own BGP AS to AS_PATH you have to specify AS number:

route-map RM-PREPEND
 set as-path prepend 123 123 123

router bgp 123
 neighbor x.x.x.x route-map RM-PREPEND out

Good luck!

Admin area