Notes on Networking#
Terminology#
| Term | Description | Notes |
|---|---|---|
| SFP+ | Small Form-factor Pluggable (SFP) | |
| SFI | Serial Framing Interface (SFI) enables high-speed data transmission in 10G SFP+ and 40G QSFP+ optical modules | |
| SerDes | Serializer/Deserializer. An integrated circuit transceiver that converts parallel data into serial data for transmission, and then converts the received serial data back into parallel form | |
| 802.11X | 802.1X (capital X) is a port-based network access control standard used for enterprise Wi-Fi authentication | |
| CCK | Complementary Code Keying. A modulation scheme used in the 802.11b wireless standard to achieve data rates of 5.5 Mbps and 11 Mbps in the 2.4 GHz band. | |
| PHY | Physical Layer. The lowest layer (Layer 1) of the OSI networking model, responsible for transmitting and receiving raw bit streams over a physical medium (like radio frequencies, copper, or fiber). | |
| OFDM | Orthogonal Frequency-Division Multiplexing. A digital transmission method that splits a single high-speed data stream into multiple slower data streams transmitted simultaneously over many closely spaced, orthogonal subcarrier frequencies. | |
| U.FL (MHF1/IPEX1) | Micro-coaxial RF connector used in compact devices. | Standard for the older, wider “mini PCIe” Wi-Fi cards (like the Intel 7260 or older Atheros cards) |
| MHF4 (IPEX4) | Even smaller micro-coaxial RF connector than U.FL. |
10G / 10-Gigabit SFI/SFP+#
Intel Wi-Fi 6 AX210/AX211/AX411 160MHz (chip-ID: 8086:2725) signal problems#
Probably caused by using U.FL instead of MHF4.
[ 3.762926] iwlwifi 0000:03:00.0: enabling device (0000 -> 0002)
[ 3.793061] iwlwifi 0000:03:00.0: Detected crf-id 0x400410, cnv-id 0x400410 wfpm id 0x80000000
[ 3.793078] iwlwifi 0000:03:00.0: PCI dev 2725/0024, rev=0x420, rfid=0x10d000
[ 3.849265] iwlwifi 0000:03:00.0: TLV_FW_FSEQ_VERSION: FSEQ Version: 0.0.2.41
[ 3.849974] iwlwifi 0000:03:00.0: loaded firmware version 86.fb5c9aeb.0 ty-a0-gf-a0-86.ucode op_mode iwlmvm
[ 4.567381] iwlwifi 0000:03:00.0: Detected Intel(R) Wi-Fi 6 AX210 160MHz, REV=0x420
[ 4.574674] iwlwifi 0000:03:00.0: WRT: Invalid buffer destination
[ 4.732038] iwlwifi 0000:03:00.0: WFPM_UMAC_PD_NOTIFICATION: 0x20
[ 4.732057] iwlwifi 0000:03:00.0: WFPM_LMAC2_PD_NOTIFICATION: 0x1f
[ 4.732071] iwlwifi 0000:03:00.0: WFPM_AUTH_KEY_0: 0x90
[ 4.732081] iwlwifi 0000:03:00.0: CNVI_SCU_SEQ_DATA_DW9: 0x0
[ 4.733573] iwlwifi 0000:03:00.0: loaded PNVM version 16611aa6
[ 4.749012] iwlwifi 0000:03:00.0: Detected RF GF, rfid=0x10d000
[ 4.818153] iwlwifi 0000:03:00.0: base HW address: XX:XX:XX:XX:XX:XX
[ 4.858768] iwlwifi 0000:03:00.0 wlp3s0: renamed from wlan0
[ 1795.417097] iwlwifi 0000:03:00.0: Registered PHC clock: iwlwifi-PTP, with index: 1Why are there MEDIATEK MT7925 802.11be 160MHz 2x2 PCIe Wireless Network Adapter [Filogic 360] (mt7925e, chip-ID: 14c3:7925) txpower quirks?#
user@workstation ~ $ sudo inxi -Nxxx
Network:
Device-1: MEDIATEK MT7925 802.11be 160MHz 2x2 PCIe Wireless Network Adapter
[Filogic 360] driver: mt7925e v: kernel pcie: gen: 2 speed: 5 GT/s
lanes: 1 bus-ID: 07:00.0 chip-ID: 14c3:7925 class-ID: 0280
IF: wlp7s0 state: up mac: XX:XX:XX:XX:XX:XX
...
user@workstatino ~ $ iw list | grep Freq -A10
Frequencies:
* 2412.0 MHz [1] (20.0 dBm)
* 2417.0 MHz [2] (20.0 dBm)
* 2422.0 MHz [3] (20.0 dBm)
* 2427.0 MHz [4] (20.0 dBm)
* 2432.0 MHz [5] (20.0 dBm)
* 2437.0 MHz [6] (20.0 dBm)
* 2442.0 MHz [7] (20.0 dBm)
* 2447.0 MHz [8] (20.0 dBm)
* 2452.0 MHz [9] (20.0 dBm)
* 2457.0 MHz [10] (20.0 dBm)
--
...
user@workstation ~ $ iwlist wlp7s0 txpower
wlp7s0 unknown transmit-power information.
Current Tx-Power=3 dBm (1 mW)
user@workstation ~ $ sudo iw --debug dev wlp7s0 set txpower fixed 19000
...
-- Debug: Received Message:
-------------------------- BEGIN NETLINK MESSAGE ---------------------------
[NETLINK HEADER] 16 octets
.nlmsg_len = 36
.type = 2 <ERROR>
.flags = 256 <ROOT>
.seq = -1774725874
.port = -92112798
[ERRORMSG] 20 octets
.error = 0 "Success"
[ORIGINAL MESSAGE] 16 octets
.nlmsg_len = 16
.type = 39 <0x27>
.flags = 5 <REQUEST,ACK>
.seq = -1774725874
.port = -92112798
--------------------------- END NETLINK MESSAGE ---------------------------[105318.427902] wlo1: Limiting TX power to 0 (-128 - 0) dBm as advertised by XX:XX:XX:XX:XX:XXHow to catch IPv6 router advertisement#
root@vault ~ # tcpdump -i tap100i0 '(udp port 546 or 547) or (icmp6 and (ip6[40] == 133 or ip6[40] == 134))' -n -vv
tcpdump: listening on tap100i0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
20:44:53.569782 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 64) fe80::ca4c:75ff:fe77:a3d9 > ff02::1: [icmp6 sum ok] ICMP6, router advertisement, length 64
hop limit 64, Flags [managed], pref medium, router lifetime 1800s, reachable time 0ms, retrans timer 0ms
source link-address option (1), length 8 (1): c8:4c:75:77:a3:d9
0x0000: c84c 7577 a3d9
mtu option (5), length 8 (1): 1500
0x0000: 0000 0000 05dc
prefix info option (3), length 32 (4): fd00:0:1400::/64, Flags [onlink, auto], valid time 2592000s, pref. time 604800s
0x0000: 40c0 0027 8d00 0009 3a80 0000 0000 fd00
0x0010: 0000 1400 0000 0000 0000 0000 0000