motivación
En ocasiones y por diversos motivos es posible que se pierda acceso vía http o ssh a un router EdgeMAX. En estos casos existe una tercera vía de conexión gracias al acceso por consola.
conectandose al router
Puesto que el router está inaccesible no podemos acceder a éste normalmente a través de la página web o a través de ssh. En cambio sí que existe la posibilidad de conectarse al equipo a través del puerto serie. Aunque se trata de un zócalo para RJ-45 no hay que confundirlo con una conexión de red y será necesario un cable, que por un lado tiene un RJ-45 y por el otro un DB9. Existen diferentes configuraciones para este cable aunque lo más cómodo es usar un cable del fabricante cisco.
Una vez conectados por serial al router es necesario utilizar un programa que permita la conexión serial. En mi caso utilizo putty con los parámetros de conexión: “Baud rate: 115200 Data bits: 8 Parity: NONE Stop bits: 1 Flow control: NONE“.
En la ventana de putty se pueder observar el proceso de inicio completo del dispositivo.
Looking for valid bootloader image....
Jumping to start of image at address 0xbfc80000
U-Boot 1.1.1 (UBNT Build ID: 4493936-g009d77b) (Build time: Sep 20 2012 - 15:48:51)
BIST check passed.
UBNT_E100 r1:2, r2:12, serial #: ---------------
Core clock: 500 MHz, DDR clock: 266 MHz (532 Mhz data rate)
DRAM: 512 MB
Clearing DRAM....... done
Flash: 4 MB
Net: octeth0, octeth1, octeth2
USB: (port 0) scanning bus for devices... 1 USB Devices found
scanning bus for storage devices...
Device 0: Vendor: USB Mass Prod.: Storage Device Rev:
Type: Removable Hard Disk
Capacity: 971.5 MB = 0.9 GB (1989632 x 512) 0
reading vmlinux.64
..................................
6865928 bytes read
argv[2]: coremask=0x3
argv[3]: root=/dev/sda2
argv[4]: rootdelay=15
argv[5]: rw
argv[6]: rootsqimg=squashfs.img
argv[7]: rootsqwdir=w
argv[8]: mtdparts=phys_mapped_flash:512k(boot0),512k(boot1),64k@3072k(eeprom)
ELF file is 64 bit
Allocating memory for mapped kernel segment, alignment: 0x400000
Allocated memory for ELF segment: addr: 0x400000, size 0x7de180
Processing PHDR 0
Loading 68ae00 bytes at 400000
Clearing 153380 bytes at a8ae00
## Loading Linux kernel with entry point: 0x008e7cd0 ...
Bootloader: Done loading app on coremask: 0x3
Linux version 3.10.20-UBNT (root@ubnt-builder2) (gcc version 4.7.0 (Cavium Inc. Version: SDK_3_1_0_p2 build 34) ) #1 SMP Tue Jun 16 12:05:05 PDT 2015
CVMSEG size: 2 cache lines (256 bytes)
Cavium Inc. SDK-3.1
bootconsole [early0] enabled
CPU revision is: 000d0601 (Cavium Octeon+)
Checking for the multiply/shift bug... no.
Checking for the daddiu bug... no.
Determined physical RAM map:
memory: 0000000007400000 @ 0000000000c00000 (usable)
memory: 0000000007c00000 @ 0000000008200000 (usable)
memory: 000000000fc00000 @ 0000000410000000 (usable)
memory: 0000000000648000 @ 0000000000400000 (usable)
memory: 0000000000048000 @ 0000000000a48000 (usable after init)
Wasting 57344 bytes for tracking 1024 unused pages
software IO TLB [mem 0x01707000-0x01747000] (0MB) mapped at [8000000001707000-8000000001746fff]
Zone ranges:
DMA32 [mem 0x00400000-0xefffffff]
Normal [mem 0xf0000000-0x41fbfffff]
Movable zone start for each node
Early memory node ranges
node 0: [mem 0x00400000-0x00a8ffff]
node 0: [mem 0x00c00000-0x07ffffff]
node 0: [mem 0x08200000-0x0fdfffff]
node 0: [mem 0x410000000-0x41fbfffff]
Primary instruction cache 32kB, virtually tagged, 4 way, 64 sets, linesize 128 bytes.
Primary data cache 16kB, 64-way, 2 sets, linesize 128 bytes.
Secondary unified cache 128kB, 8-way, 128 sets, linesize 128 bytes.
PERCPU: Embedded 10 pages/cpu @8000000001784000 s11776 r8192 d20992 u40960
Built 1 zonelists in Zone order, mobility grouping on. Total pages: 125887
Kernel command line: bootoctlinux $loadaddr coremask=0x3 root=/dev/sda2 rootdelay=15 rw rootsqimg=squashfs.img rootsqwdir=w mtdparts=phys_mapped_flash:512k(boot0),512k(boot1),64k@3072k(eeprom) console=ttyS0,115200
PID hash table entries: 2048 (order: 2, 16384 bytes)
Dentry cache hash table entries: 65536 (order: 7, 524288 bytes)
Inode-cache hash table entries: 32768 (order: 6, 262144 bytes)
Memory: 495244k/510528k available (5073k kernel code, 15284k reserved, 1355k data, 288k init, 0k highmem)
Hierarchical RCU implementation.
Additional per-CPU info printed with stalls.
NR_IRQS:255
Calibrating delay loop (skipped) preset value.. 1000.00 BogoMIPS (lpj=5000000)
pid_max: default: 32768 minimum: 501
Security Framework initialized
Mount-cache hash table entries: 256
Checking for the daddi bug... no.
SMP: Booting CPU01 (CoreId 1)...
CPU revision is: 000d0601 (Cavium Octeon+)
Brought up 2 CPUs
NET: Registered protocol family 16
bio: create slab <bio-0> at 0
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
Switching to clocksource OCTEON_CVMCOUNT
NET: Registered protocol family 2
TCP established hash table entries: 4096 (order: 4, 65536 bytes)
TCP bind hash table entries: 4096 (order: 4, 65536 bytes)
TCP: Hash tables configured (established 4096 bind 4096)
TCP: reno registered
UDP hash table entries: 256 (order: 1, 8192 bytes)
UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
NET: Registered protocol family 1
octeon_pci_console: Console not created.
/proc/octeon_perf: Octeon performance counter interface loaded
HugeTLB registered 2 MB page size, pre-allocated 0 pages
squashfs: version 4.0 (2009/01/31) Phillip Lougher
Registering unionfs 2.5.13 (for 3.10.34)
msgmni has been set to 967
io scheduler noop registered
io scheduler cfq registered (default)
Serial: 8250/16550 driver, 6 ports, IRQ sharing disabled
1180000000800.serial: ttyS0 at MMIO 0x1180000000800 (irq = 34) is a OCTEON
console [ttyS0] enabled, bootconsole disabled
console [ttyS0] enabled, bootconsole disabled
1180000000c00.serial: ttyS1 at MMIO 0x1180000000c00 (irq = 35) is a OCTEON
loop: module loaded
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
OcteonUSB 16f0010000000.usbc: Octeon Host Controller
OcteonUSB 16f0010000000.usbc: new USB bus registered, assigned bus number 1
OcteonUSB 16f0010000000.usbc: irq 56, io mem 0x00000000
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 1 port detected
OcteonUSB: Registered HCD for port 0 on irq 56
usbcore: registered new interface driver usb-storage
octeon_wdt: Initial granularity 5 Sec
TCP: cubic registered
NET: Registered protocol family 17
NET: Registered protocol family 15
Bootbus flash: Setting flash for 4MB flash at 0x1f800000
phys_mapped_flash: Found 1 x16 devices at 0x0 in 8-bit bank. Manufacturer ID 0x0000c2 Chip ID 0x0000a7
Amd/Fujitsu Extended Query Table at 0x0040
Amd/Fujitsu Extended Query version 1.1.
phys_mapped_flash: Swapping erase regions for top-boot CFI table.
number of CFI chips: 1
3 cmdlinepart partitions found on MTD device phys_mapped_flash
Creating 3 MTD partitions on "phys_mapped_flash":
0x000000000000-0x000000080000 : "boot0"
0x000000080000-0x000000100000 : "boot1"
0x000000300000-0x000000310000 : "eeprom"
Waiting 15sec before mounting root device...
usb 1-1: new high-speed USB device number 2 using OcteonUSB
usb-storage 1-1:1.0: USB Mass Storage device detected
scsi0 : usb-storage 1-1:1.0
scsi 0:0:0:0: Direct-Access USB Mass Storage Device PQ: 0 ANSI: 0 CCS
sd 0:0:0:0: [sda] 1989632 512-byte logical blocks: (1.01 GB/971 MiB)
sd 0:0:0:0: [sda] Write Protect is off
sd 0:0:0:0: [sda] No Caching mode page found
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] No Caching mode page found
sd 0:0:0:0: [sda] Assuming drive cache: write through
sda: sda1 sda2
sd 0:0:0:0: [sda] No Caching mode page found
sd 0:0:0:0: [sda] Assuming drive cache: write through
sd 0:0:0:0: [sda] Attached SCSI removable disk
kjournald starting. Commit interval 3 seconds
EXT3-fs (sda2): using internal journal
EXT3-fs (sda2): mounted filesystem with journal data mode
VFS: Mounted root (unionfs filesystem) on device 0:11.
Freeing unused kernel memory: 288K (ffffffffc0648000 - ffffffffc0690000)
Algorithmics/MIPS FPU Emulator v1.5
INIT: version 2.88 booting
INIT: Entering runlevel: 2
[ ok ] Starting routing daemon: rib.
[ ok ] Starting EdgeOS router: migrate rl-system configure.
Welcome to EdgeOS ubnt ttyS0
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